Universidad Tecnológica de Querétaro

Transcription

Universidad
Tecnológica de
Querétaro
Digitally signed by Universidad
Tecnológica de Querétaro
DN: CN = Universidad Tecnológica
de Querétaro, C = MX, O = UTEQ
Date: 2004.12.16 10:05:23 -06'00'
UNIVERSIDAD TECNOLÓGICA DE QUERÉTARO
Voluntad. Conocimiento. Servicio
IMPLEMENTAR UN INDICADOR DIGITAL (LCD) A LA MÁQUINA
ENVASADORA DE BOLIS
JAM GELATINAS, BOLIS Y POLIETILENO
Reporte de Estadía para obtener
el Título de Técnico Superior Universitario
en Electrónica y Automatización
NOMBRE DEL ASESOR DE EMPRESA:
CHRISTIAN BUENO SANTILLÁN
NOMBRE DEL ASESOR DE LA ESCUELA:
FABIO TOMÁS MORENO ORTIZ
NOMBRE DEL ALUMNO:
ISRAEL BARBOSA ORTIZ
Santiago de Querétaro, Qro
Agosto de 2004
OFICIO DE AUTORIZACION.
3
DEDICATORIAS
Este trabajo no hubiera sido posible sin la colaboración de todas aquellas personas
(familiares, amigos y profesores) que me apoyaron durante su realización, por lo que les
estoy muy agradecido y les dedico afectuosamente este reporte.
A quienes confiaron en mis estudios y me alentaron hasta lograr terminarlos.
A mis papás y hermanos, por haberme dado la oportunidad de dar un paso más adelante
en mis estudios.
A mis tíos Roxana y Jesús, por darme el apoyo moral y económico necesario para poder
terminar esta etapa de estudio en mi vida.
A todos ellos muchas gracias.
4
ÍNDICE
Pág.
INTRODUCCIÓN------------------------------------------------------------------8
CAPÍTULO I.- ASPECTOS GENERALES DE LA EMPRESA-----------------------9
1.1 Antecedentes de la empresa-----------------------------------------------------------------10
1.2 Misión------------------------------------------------------------------------------------------10
1.3 Visión------------------------------------------------------------------------------------------11
1.4 Política de calidad---------------------------------------------------------------------------11
1.5 Organización----------------------------------------------------------------------------------11
1.6 Campo de desarrollo nacional--------------------------------------------------------------13
1.7 Proceso general de producción-------------------------------------------------------------13
CAPÍTULO II.- EL PROYECTO------------------------------------------------------------15
2.1 Antecedentes-----------------------------------------------------------------------------------16
2.2 Definición del proyecto-----------------------------------------------------------------------16
2.3 Objetivo-----------------------------------------------------------------------------------------16
2.4 Alcance-----------------------------------------------------------------------------------------16
CAPÍTULO III.- PLAN DE TRABAJO----------------------------------------------------17
3.1 Separación de actividades-------------------------------------------------------------------18
3.2 Secuencia de actividades--------------------------------------------------------------------19
3.3 Asignación de tiempos-----------------------------------------------------------------------20
3.4 Gráfica de Gantt------------------------------------------------------------------------------21
CAPÍTULO IV.- MARCO TEÓRICO------------------------------------------------------23
4.1 ¿Qué es un microcontrolador?--------------------------------------------------------------24
4.1.1 Un poco de historia------------------------------------------------------------------------24
4.1.2 Diferencia entre microprocesador y microcontrolador--------------------------------25
5
Pág
4.1.3 Ventajas de un microcontrolador frente a un microprocesador-----------------------26
4.1.4 Los microcontroladores hoy en día-------------------------------------------------------27
4.1.5 Tipos de arquitecturas de un microcontrolador.----------------------------------------28
4.2 Pantalla de cristal líquido (LCD).-----------------------------------------------------------30
4.2.1 Los caracteres del LCD--------------------------------------------------------------------31
4.2.2 Principio de funcionamiento del LCD---------------------------------------------------32
4.2.3 Diversidad de módulos LCD--------------------------------------------------------------34
4.2.4 Tipos de memorias del LCD---------------------------------------------------------------34
4.2.5 Características principales-----------------------------------------------------------------36
4.2.6 Descripción de pines------------------------------------------------------------------------37
4.2.7 Tensiones máximas-------------------------------------------------------------------------38
4.2.8 Características eléctricas------------------------------------------------------------------38
4.3 Juegos de instrucciones-----------------------------------------------------------------------39
4.3.1 Comando de borrar display (LCD)-------------------------------------------------------39
4.3.2 Dirección de la memoria DD RAM------------------------------------------------------39
4.3.3 Comando de lectura BUSY FLAG-------------------------------------------------------40
4.3.4 Comando de escritura en la memoria CG O DD RAM--------------------------------40
4.3.5 Comando de lectura de la memoria CG O DD RAM---------------------------------41
4.4 Esquema del PIC16F84----------------------------------------------------------------------41
4.4.1 PIC16F84------------------------------------------------------------------------------------42
4.4.2 Características periféricas------------------------------------------------------------------42
4.4.3 Características especiales para el microcontrolador------------------------------------43
4.4.4 Tecnología CMOS--------------------------------------------------------------------------43
4.4.5 Descripción general-------------------------------------------------------------------------44
4.4.6 Descripción de pines------------------------------------------------------------------------45
4.4.7 Set de 35 instrucciones---------------------------------------------------------------------46
CAPÍTULO V.- DESARROLLO DEL PROYECTO-------------------------------------48
5.1 Antecedentes-----------------------------------------------------------------------------------49
6
Pág
5.2 Elaboración de una fuente de 5 V-----------------------------------------------------------49
5.2.1 Ensamble de componente en la tarjeta---------------------------------------------------50
5.3 Elaboración del circuito electrónico del microcontrolador (PIC16F84)---------------50
5.3.1 Ensamble de los componentes en la tarjeta----------------------------------------------51
5.4 Programa para el microcontrolador PIC16F84 -------------------------------------------52
5.5 Reductor de tensión---------------------------------------------------------------------------54
5.6 Ensamble de las tarjetas en la máquina envasadora de bolis----------------------------54
5.6.1 Cableado en la máquina envasadora de bolis-------------------------------------------55
CAPÍTULO VI.- EVALUACIÓN ECONÓMICA----------------------------------------56
6.1 Evaluación económica------------------------------------------------------------------------57
CAPÍTULO VII.- RESULTADOS OBTENIDOS-----------------------------------------59
7.1 Resultados cumplidos------------------------------------------------------------------------60
CONCLUSIONES-------------------------------------------------------------------------------61
Conclusión-----------------------------------------------------------------------------------------62
BIBLIOGRAFÍA---------------------------------------------------------------------------------63
Bibliografía-----------------------------------------------------------------------------------------64
ANEXOS-------------------------------------------------------------------------------------------65
Programa del microcontrolador-------------------------------------------------------------------Diagrama eléctrico del sistema mínimo y PCB (microcontrolador)--------------------------Diagrama eléctrico y PCB de la fuente de 5 volts----------------------------------------------Hojas de datos del indicador digital (LCD)------------------------------------------------------Hojas de datos del microcontrolador---------------------------------------------------------------
7
INTRODUCCIÓN
El presente trabajo está dirigido a todas aquellas personas que estén interesadas sobre el
conocimiento e interpretación de los aspectos más importantes referentes a los
microcontroladores y el indicador digital (LCD).
Para la elaboración de este trabajo se requirió de un trabajo de investigación,
documentado en fuentes bibliográficas que recogen estudios especializados sobre
microcontroladores e indicadores digitales (LCD).
Para introducirse en el mundo de los microcontroladores es necesario partir de la
definición de lo que son un microcontrolador y un indicador digital (LCD):
Un microcontrolador es un dispositivo electrónico capaz de llevar a cabo procesos
lógicos. Estos procesos o acciones son programados en lenguaje ensamblador por el
usuario, y son introducidos al microcontrolador a través de un programador. Así como se
abarcaran unas de sus principales características y tipos de arquitectura de un
microcontrolador.
El indicador digital también conocido como pantalla de cristal líquido o LCD (Liquid
Crystal Display) es un dispositivo microcontrolador de visualización gráfico para la
presentación de caracteres, símbolos o incluso dibujos (en algunos modelos), en este
caso dispone de 2 filas de 16 caracteres cada una y cada carácter dispone de una matriz
de 5x8 puntos.
Este indicador digital (LCD) se aplicará en la máquina envasadora de bolis que está
dentro de la empresa, la cual no tiene con que visualizar de una manera rápida en que
modo de operación se encuentra (automático, doble efecto y semiautomático), por ello
se elaboró este trabajo para permitirle al operador visualizar en que modo de operación
se encuentra la máquina.
8
CAPÍTULO I
ASPECTOS GENERALES
DE LA EMPRESA
9
1.1 Antecedentes de la empresa
JAM es una microempresa que se ubica en el Estado de Querétaro, en la calle Hidalgo
#56, en la colonia San José de los Olvera del Municipio Corregidora. La historia de JAM
comienza en 1986 por el señor Jaime Solís Gutiérrez, quien fue incorporado al negocio
de bolis por un conocido. La empresa contaba solamente con 3 integrantes y con una
máquina envasadora de bolis que era de pedales. En ese entonces diariamente
preparaban 5 litros de cada sabor de bolis (piña, fresa, limón, uva y naranja). La primera
venta grande que tuvo la empresa fue de 14 paquetes, y para dar a conocer su producto
implementaron la venta personal que era tienda por tienda. Después se tomó la decisión
de visitar también dulcerías, en las que se llegó a vender hasta 100 paquetes.
Después de analizar la situación, se buscó la manera de vender directamente al
consumidor final. Por tal motivo, empezaron a asistir a tianguis, y las ventas fueron
satisfactorias. Esto fue lo que motivó aún más a que las ventas se realizaran en los
tianguis. La segunda máquina que se creó para el llenado de los bolis era de 5 tubos, uno
para cada sabor. Para tener un gasto menor en la compra de bolsas para la elaboración de
los bolis, se produjo una máquina rudimentaria de fabricación de polietileno tubular, la
cual producía 20 kgs, cada 16 horas. Actualmente la empresa cuenta con una máquina
envasadora productora de bolis automática de 10 tubos.
Un aspecto muy sobresaliente de esta microempresa es que el señor Jaime Solís está
fabricando sus propias máquinas, lo cual hace posible que se estén vendiendo máquinas
productoras de bolis automáticas o semiautomáticas en diversos lugares de la república,
como Monterrey, Morelia y varios más.
1.2 Misión
Ser una empresa productora de insumos de consumo final para los mercados
alimenticios y consumidores con excelente calidad a un precio competitivo, todo esto a
través de tecnología propia atendiendo las necesidades del mercado.
10
1.3 Visión
Que la empresa JAM sea conocida en el ámbito nacional compitiendo con las mejores
empresas en su género, innovando tecnología para un desarrollo constante y duradero.
1.4 Política de calidad
Ofrecer un producto o servicio, cuidando los aspectos más importantes para que el
cliente o consumidor quede satisfecho.
1.5 Organización
En el siguiente organigrama se presenta la organización de los departamentos de la
empresa JAM gelatinas, bolis y polietileno.
GERENTE
GENERAL
CONTABILIDAD
ADMINISTRACIÓN
FINANZAS
PRODUCCIÓN
SISTEMAS
MANTENIMIENTO
COMPRAS
VENTAS
Figura 1.1. Organigrama de JAM.
11
Gerente general: Responsable de coordinar y llevar el buen funcionamiento de cada uno
de los departamentos que constituyen a la empresa.
Departamento de contabilidad: Encargado de tener en orden toda la contabilidad de la
empresa, además de hacer las declaraciones fiscales correspondientes ante la Secretaría
de Hacienda y Crédito Público, así como verificar y controlar los ingresos y egresos de
la empresa.
Departamento de finanzas: Se verifica constantemente el capital con el que cuenta la
empresa. Se hacen los presupuestos para los planes que desea llevar a cabo la empresa.
Se determina el presupuesto para cada departamento.
Departamento de sistemas: Se desarrollan todos los programas para analizar y facilitar
las operaciones que realice cada departamento, tales como entradas y salidas de
mercancías del almacén, facturación, nómina, corte de caja y control de ventas.
Departamento de producción: La empresa produce 3 diferentes productos: Polietileno
bolis y gelatinas, de estos dos últimos se producen 5 sabores diferentes. El departamento
es responsable de tener la producción diaria, así como de verificar que el producto esté
en buenas condiciones y de informar la falta de materia prima al departamento de
compras.
Departamento de mantenimiento: Es el encargado de mantener en buen estado y en
condiciones constantes de trabajo las máquinas utilizadas en producción.
Departamento Administrativo: Es responsable de administrar los recursos de la empresa
y se encarga de los sueldos del personal.
12
Departamento de compras: Se encarga de abastecer a los demás departamentos de la
empresa así como de evaluar a los proveedores que surten de materiales a cada
departamento.
Departamento de ventas: Es responsable de tener un control sobre las ventas de todas las
áreas de producción. Cada mes entrega gráficas de las ventas de los bolis y gelatinas.
1.6 Campo de desarrollo nacional
La empresa JAM ha tenido un importante desenvolvimiento comercial, principalmente
en la capital del Estado de Querétaro, pero incluyendo también algunos de sus
municipios como Cadereyta, San Juan y Tequisquiapan, y municipios cercanos de otros
estados, tales como: San Miguel de Allende y Celaya. Su principal mercado de acción de
los bolis y gelatinas está en los niños.
Gracias a su desarrollo tecnológico interno, la empresa JAM cuenta con la posibilidad de
abastecer la venta de polietileno tubular a otros estados, ya que en la mayoría de estos
no se fabrica este tipo de polietileno tubular.
1.7 Proceso general de producción
En la empresa JAM, se utiliza un sistema de producción continuo, a pesar de que se
tienen altibajos en la venta de algunos productos en las temporadas de invierno o clima
frío, lo único que se hace es disminuir la cantidad de determinados productos.
Para dar un ejemplo más claro de los pasos a seguir en la producción se muestra el
siguiente diagrama de bloques.
13
VERIFICACIÓN DE
LA CALIDAD DE
MATERIA PRIMA
RECEPCIÓN
DE MATERIA
PRIMA
ENVASADO
DE
LÍQUIDO
EMPACADO
DE
BOLIS
CLASIFICACIÓN
DE
BOLIS
PREPARACIÓN
DE LÍQUIDO
DE BOLIS
VERIFICACIÓN
DE CALIDAD
DE BOLIS
ALMACENAMIENTO
DE PRODUCTO
TERMINADO
Figura 1.2. Proceso general de producción.
14
CAPÍTULO II
EL PROYECTO
15
2.1 Antecedentes
La máquina envasadora de bolis actual no cuenta con un dispositivo que muestre los
diferentes modos de manejo: automática, automático doble y semiautomática. Por este
motivo se llegó a la conclusión de que es necesario implementar un indicador digital,
para que el operador vea de manera inmediata en qué posición se encuentra la máquina.
2.2 Definición del proyecto
Implementar un indicador (LCD) a la máquina envasadora de bolis. La función principal
que tendrá este indicador es mostrar en una pantalla el modo de operación en la que se
encuentra la máquina envasadora.
2.3 Objetivo
Al implementar este indicador deberá a parecer el modo de operación en la que se
encuentra la máquina ya sea automática, automático doble o semiautomática, para que el
operador visualice en que modo se encuentra la máquina.
2.4 Alcance
Al terminó de la estadía, al cliente se le entregará el indicador digital en funcionamiento,
así como toda la documentación referente al indicador y los siguientes programas: el
MPL y el programador para PICs, ya que el funcionamiento del indicador se basa en un
microcontrolador.
1.- Que el proyecto se acabe en el tiempo esperado tanto teórico como físico.
2.- Entregar las tarjetas al asesor de empresa.
3.- Hacer las pruebas con el sistema mínimo.
4.- Dejar la información necesaria en la empresa para que si algún día quieren
implementar el indicador digital en todas sus máquinas que elaboran, sea fácil hacerlo.
5.- El proyecto sea lo más económico para la empresa y que ésta quede satisfecha con el
trabajo.
16
CAPÍTULO III
PLAN DE TRABAJO
17
3.1 Separación de actividades
a) Conocer bien el funcionamiento de la máquina a la cual se le implementará el
indicador digital (LCD).
b) Buscar información sobre el funcionamiento del indicador digital (LCD).
c) Buscar información sobre todas las partes que componen la máquina envasadora de
bolis.
d) Utilizar el sistema mínimo ya elaborado en la escuela para hacer pruebas con el
indicador digital (LCD), antes de realizar el proyecto final.
e) Reducir las funciones y hacer el diagrama en OrCAD.
f) Mandar a serigrafiar el diagrama del sistema mínimo.
g) Hacer la lista del material que llevará el sistema mínimo.
h) Hacer presupuesto del costo del material para comprarlo.
i) Soldar el material que llevará el sistema mínimo.
j) Hacer un reductor de tensión, comprar el material para armarlo y cotizar precios.
k) Montar las tarjetas dentro del panel de control de la máquina envasadora de bolis.
l) Soldar el material que lleva el reductor de tensión.
m) Hacer el diagrama del reductor de tensión en OrCAD.
n) Mandar a serigrafiar el diagrama del reductor de tensión.
o) Cotizar precios de indicadores digitales (LCDs).
p) Hacer el programa para el PIC que lleva el sistema mínimo para el control del LCD.
q) Conseguir los programas de: Programador para PIC, MPLAB, OrCAD y Proyect.
18
3.2 Secuencia de actividades
1.- Conocer bien el funcionamiento de la máquina a la cual se le implementará el
indicador digital (LCD).
2.- Conseguir los programas de: Programador para PIC, MPLAB, OrCAD y Proyect.
3.- Buscar información sobre el funcionamiento del indicador digital (LCD).
4.- Cotizar precios de indicadores digitales (LCDs).
5.- Buscar información sobre todas las partes que componen la máquina envasadora de
bolis.
6.- Hacer el programa para el PIC que lleva el sistema mínimo para el control del LCD.
7.- Utilizar el sistema mínimo ya elaborado en la escuela para hacer pruebas con el
indicador digital (LCD), antes de realizar el proyecto final.
8.- Reducir las funciones y hacer el diagrama en OrCAD.
9.- Mandar a serigrafiar el diagrama del sistema mínimo.
10.- Hacer la lista del material que llevará el sistema mínimo.
11.- Hacer presupuesto del costo del material para comprarlo.
12.- Soldar el material que llevará el sistema mínimo.
13.- Hacer un reductor de tensión, comprar el material para armarlo y cotizar precios.
14.- Hacer el diagrama del reductor de tensión en OrCAD.
15.- Mandar a serigrafiar el diagrama del reductor de tensión.
16.- Soldar el material que lleva el reductor de tensión.
17.- Montar las tarjetas dentro del panel de control de la máquina envasadora de bolis.
19
3.3 Asignación de tiempos
Tiempo
en días
Ruta crítica
Actividad
Actividades Secuencia Estándar Óptimo Medio Pésimo
0
1,2
0
0
0
0
Empresa y proyecto.
1
4
9
10
8
12
Programas.
2
3
7
9
6
10
Información del LCD.
3
5
6
7
6
8
Costo del LCD.
4
5
6
5
7
Máquina.
5
6
17
20
15
22
Programa del PIC.
Sistema mínimo.
6
7
7
8,10
5
6
6
7
5
6
7
8
Diseño de sistema.
8
6
7
6
8
Serigrafiar.
9
11
3
4
3
5
Material Sist. Mín.
10
9
1
1
1
1
Costo y comprar material.
11
12
7
9
6
10
Soldar material.
12
13
2
3
2
4
Diagrama de reductor.
13
14
4
5
4
6
Diseño de reductor.
14
15
3
4
3
5
Serigrafiar.
15
16
3
4
3
5
Soldar material.
16
17
2
3
2
4
Montar tarjetas.
17
5
6
5
7
Tabla 3.1 Asignación de tiempos.
20
3.4 Gráfica de Gantt.
21
22
CAPÍTULO IV
MARCO TEÓRICO
23
4.1 Microcontrolador
¿Qué es un microcontrolador?
Un microcontrolador es un dispositivo electrónico capaz de llevar a cabo procesos
lógicos. Estos procesos o acciones son programados en lenguaje ensamblador por el
usuario, y son introducidos al microcontrolador a través de un programador.
4.1.1 Un poco de historia
Inicialmente cuando no existían los microprocesadores las personas se ingeniaban en
diseñar sus circuitos electrónicos y los resultados estaban expresados en diseños que
implicaban muchos componentes electrónicos y cálculos matemáticos. Un circuito
lógico básico requería de muchos elementos electrónicos basados en transistores,
resistencias, etc, lo cual desembocaba en circuitos con muchos ajustes y fallos; pero en
el año 1971 apareció el primer microprocesador el cual originó un cambio decisivo en
las técnicas de diseño de la mayoría de los equipos. Al principio se creía que el manejo
de un microprocesador era para aquellas personas con un coeficiente intelectual muy
alto; por el contrario, con la aparición de este circuito integrado todo sería mucho más
fácil de entender y los diseños electrónicos serían mucho más pequeños y simplificados.
Entre los microprocesadores más conocidos tenemos el popular Z-80 y el 8085. Los
diseñadores de equipos electrónicos ahora tenían equipos que podían realizar mayor
cantidad de tareas en menos tiempo y su tamaño se redujo considerablemente; sin
embargo, después de cierto tiempo aparece una nueva tecnología llamada
microcontrolador que simplifica aun más el diseño electrónico.
24
4.1.2 Diferencias entre microprocesador y microcontrolador
Si tiene la oportunidad de realizar un diseño con un microprocesador podrá observar que
dependiendo del circuito se requieren algunos circuitos integrados adicionales además
del microprocesador, como por ejemplo: memorias RAM para almacenar los datos
temporalmente y memorias ROM para almacenar el programa que se encarga del
proceso del equipo, un circuito integrado para los puertos de entrada y salida y
finalmente un decodificador de direcciones.
Figura 4.1 Estructura de un sistema abierto basado en un microprocesador. La
disponibilidad de los buses en el exterior permite que se configure a la medida de la
aplicación.
Un microcontrolador es un solo circuito integrado que contiene todos los elementos
electrónicos que se utilizaban para hacer funcionar un sistema basado con un
microprocesador; es decir contiene en un solo integrado la Unidad de Proceso, la
memoria RAM, memoria ROM, puertos de entrada, salidas y otros periféricos, con la
consiguiente reducción de espacio.
El microcontrolador es en definitiva un circuito integrado que incluye todos los
componentes de un computador. Debido a su reducido tamaño es posible montar el
25
controlador en el propio dispositivo al que gobierna. En este caso el controlador recibe el
nombre de controlador empotrado.
Figura 4.2 El microcontrolador es un sistema cerrado. Todas las partes del procesador
están contenidas en su interior y sólo salen al exterior las líneas que gobiernan los
periféricos.
4.1.3 Ventajas de un microcontrolador frente a un microprocesador
Estas ventajas son reconocidas inmediatamente para aquellas personas que han trabajado
con los microprocesadores y después pasaron a trabajar con los microcontroladores.
Estas son las diferencias más importantes:
Por ejemplo la configuración mínima básica de un microprocesador estaba constituida
por un Micro de 40 Pines, Una memoria RAM de 28 Pines, una memoria ROM de 28
Pines y un decodificador de direcciones de 18 pines; pero un microcontrolador incluye
todo estos elementos en un solo Circuito Integrado por lo que implica una gran ventaja
en varios factores: En el circuito impreso por su amplia simplificación de circuitería, el
costo para un sistema basado en microcontrolador es mucho menor y, lo mejor de todo,
el tiempo de desarrollo de su proyecto electrónico se disminuye considerablemente.
26
4.1.4 Los microcontroladores hoy en día
Los microcontroladores están conquistando el mundo. Están presentes en nuestro
trabajo, en nuestra casa y en nuestra vida, en general. Se pueden encontrar controlando
el funcionamiento de los ratones y teclados de los computadores, en los teléfonos, en los
hornos de microondas y los televisores de nuestro hogar. Pero la invasión acaba de
comenzar y el nacimiento del siglo XXI será testigo de la conquista masiva de estos
diminutos computadores, que gobernarán la mayor parte de los aparatos que fabricará y
usara el ser humano.
Cada vez existen más productos que incorporan un microcontrolador con el fin de
aumentar sustancialmente sus prestaciones, reducir su tamaño y costo, mejorar su
fiabilidad y disminuir el consumo.
Algunos fabricantes de microcontroladores superan el millón de unidades de un modelo
determinado producidas en una semana. Este dato puede dar una idea de la masiva
utilización de estos componentes.
Los microcontroladores están siendo empleados en multitud de sistemas presentes en
nuestra vida diaria, como pueden ser juguetes, horno de microondas, frigoríficos,
televisores, computadoras, impresoras, módems, el sistema de arranque de nuestro
coche, etc. Y otras aplicaciones con las que seguramente no estaremos tan
familiarizados, como instrumentación electrónica, control de sistemas en una nave
espacial, etc. Una aplicación típica podría emplear varios microcontroladores para
controlar pequeñas partes del sistema. Estos pequeños controladores podrían
comunicarse entre ellos y con un procesador central, probablemente más potente, para
compartir la información y coordinar sus acciones, como de hecho ocurre ya
habitualmente en cualquier PC.
27
4.1.5 Tipos de arquitecturas de microcontroladores
- Arquitectura Von Neumann
La arquitectura tradicional de computadoras y microprocesadores está basada en la
arquitectura Von Neumann, en la cual la unidad central de proceso (CPU), está
conectada a una memoria única donde se guardan las instrucciones del programa y los
datos.
El tamaño de la unidad de datos o instrucciones está fijado por el ancho del bus que
comunica la memoria con la CPU. Así un microprocesador de 8 bits con un bus de 8
bits, tendrá que manejar datos e instrucciones de una o más unidades de 8 bits (bytes) de
longitud. Si tiene que acceder a una instrucción o dato de más de un byte de longitud,
tendrá que realizar más de un acceso a la memoria.
Y el tener un único bus hace que el microprocesador sea más lento en su respuesta, ya
que no puede buscar en memoria una nueva instrucción mientras no finalicen las
transferencias de datos de la instrucción anterior.
Resumiendo todo lo anterior, las principales limitaciones que nos encontramos con la
arquitectura Von Neumann son:
1º. La limitación de la longitud de las instrucciones por el bus de datos, que hace que el
microprocesador tenga que realizar varios accesos a memoria para buscar instrucciones
complejas.
2º. La limitación de la velocidad de operación a causa del bus único para datos e
instrucciones que no deja acceder simultáneamente a unos y otras, lo cual impide
superponer ambos tiempos de acceso.
28
Figura 4.3 Arquitectura Von Neumann.
La arquitectura Harvard tiene la unidad central de proceso (CPU) conectada a dos
memorias (una con las instrucciones y otra con los datos) por medio de dos buses
diferentes. Una de las memorias contiene solamente las instrucciones del programa
(Memoria de Programa), y la otra sólo almacena datos (Memoria de Datos).Ambos
buses son totalmente independientes y pueden ser de distintos anchos. Para un
procesador de Set de Instrucciones Reducido, o RISC (Reduced Instrucción Set
Computer), el set de instrucciones y el bus de memoria de programa pueden diseñarse de
tal manera que todas las instrucciones tengan una sola posición de memoria de programa
de longitud.
Además, al ser los buses independientes, la CPU puede acceder a los datos para
completar la ejecución de una instrucción, y al mismo tiempo leer la siguiente
instrucción a ejecutar.
Ventajas de esta arquitectura:
1º. El tamaño de las instrucciones no esta relacionado con el de los datos, y por lo tanto
puede ser optimizado para que cualquier instrucción ocupe una sola posición de
memoria de programa, logrando así mayor velocidad y menor longitud de programa.
2º. El tiempo de acceso a las instrucciones puede superponerse con el de los datos,
logrando una mayor velocidad en cada operación.
Una pequeña desventaja de los procesadores con arquitectura Harvard, es que deben
poseer instrucciones especiales para acceder a tablas de valores constantes que pueda ser
necesario incluir en los programas, ya que estas tablas se encontrarán físicamente en la
memoria de programa (por ejemplo en la EPROM de un microprocesador).
29
Figura 4.4 Arquitectura Harvard.
4.2 Pantalla de cristal líquido (LCD)
El indicador digital también conocido como pantalla de cristal líquido o LCD (Liquid
Crystal Display) es un dispositivo microcontrolador de visualización gráfico para la
presentación de caracteres, símbolos o incluso dibujos (en algunos modelos), en este
caso dispone de 2 filas de 16 caracteres cada una y cada carácter dispone de una matriz
de 5x8 puntos (pixels), aunque los hay de otro número de filas y caracteres. Este
dispositivo esta gobernado internamente por un microcontrolador Hitachi 44780 y regula
todos los parámetros de presentación. Este modelo es el más comúnmente usado y esta
información se basará en el manejo de este u otro LCD compatible.
Figura 4.5 Indicador digital.
Para su funcionamiento el indicador digital (LCD), debe estar conectado a un circuito
impreso en el que estén integrados los controladores del display y los pines para la
conexión del display. Sobre el circuito impreso se encuentra el indicador digital (LCD),
rodeado por una estructura metálica que lo protege. En este tipo de indicadores digitales
30
(LCD) se pueden visualizar 2 líneas de 16 caracteres cada una, es decir, 2x16=32
caracteres.
4.2.1 Los caracteres del LCD
Dispone de una matriz de 5x8 puntos para representar cada carácter. En total se pueden
representar 256 caracteres diferentes. 240 caracteres están grabados dentro del LCD y
representan las letras mayúsculas, minúsculas, signos de puntuación, números, etc. Tiene
8 caracteres que pueden ser definidos por el usuario.
En la siguiente tabla se muestran los caracteres más importantes que es capaz de
representar la pantalla LCD. No están representados los caracteres correspondientes a
los códigos desde el $80 hasta el $FF, que corresponden a símbolos extraños. Los
códigos comprendidos entre el 0 y el 7 están reservados para que el usuario los defina.
Código Carácter Código Carácter Código Carácter Código Carácter Código Carácter Código Carácter
$20
$21
$22
$23
$24
$25
$26
$27
$28
$29
$2A
$2B
$2C
$2D
$2E
$2F
espacio
!
“
#
$
%
&
‘
)
(
*
+
,
.
/
$30
$31
$32
$33
$34
$35
$36
$37
$38
$39
$3A
$3B
$3C
$3D
$3E
$3F
0
1
2
3
4
5
6
7
8
9
:
;
<
=
>
?
$40
$41
$42
$43
$44
$45
$46
$47
$48
$49
$4A
$4B
$4C
$4D
$4E
$4F
A
B
C
D
E
F
G
H
I
J
K
L
M
N
O
$50
$51
$52
$53
$54
$55
$56
$57
$58
$59
$5A
$5B
$5C
$5D
$5E
$5F
P
Q
R
S
T
U
V
W
X
Y
Z
[
]
^
-
$60
$61
$62
$63
$64
$65
$66
$67
$68
$69
$6A
$6B
$6C
$6D
$6E
$6F
a
b
c
d
e
f
g
h
i
J
k
l
m
n
o
$70
$71
$72
$73
$74
$75
$76
$77
$78
$79
$7A
$7B
$7C
$7D
$7E
$7F
p
q
r
s
t
u
v
w
x
y
z
{
}
Tabla 4.1 Caracteres del LCD.
31
4.2.2 Principio de funcionamiento del indicador digital (LCD)
Hemos visto que las moléculas de cristal líquido son intrínsecamente anisótropas aunque
el desorden en equilibrio térmico da lugar a que un panel lleno de tales moléculas
produzca un comportamiento isótropo. Si se aplica un campo eléctrico o, dependiendo
del tipo de cristal líquido, si se aumenta la temperatura, las moléculas de cristal líquido
se pueden orientar y dar lugar a un comportamiento birrefringente. Una de las
aplicaciones de este comportamiento aparece en la formación de imágenes en pantallas
de ordenadores, de las calculadoras o
en relojes digitales. El principio de
funcionamiento es sencillo, y se muestra en la figura 4.6. Las celdillas que forman los
números están llenas de moléculas de cristal líquido y conectada a electrodos que
permiten activar el campo en unas y no en otras. Las celdas activadas son las que se ven
oscuras. De las figuras, se puede inducir que el resto de la radiación que no pasa por las
celdas, está linealmente polarizada, dado que con un polarizador podemos llegar a
extinguirla.
Figura 4.6 Funcionamiento del LCD.
En la figura 4.6 se observar que la luz despolarizada pasa a través del primer polarizador
y queda polarizada verticalmente. Las celdas de cristal líquido actúan como láminas
retardadoras con sus ejes a 450 y se calculan para que produzcan un desfase de p/2. Con
ello la luz pasa a ser circularmente polarizada dextrógira. Esta luz se refleja en un espejo
por lo que cambia a circular levógira. Pasa de nuevo por la lámina y se produce un
nuevo retraso de p/2. En total experimenta un desfase de p. Por lo tanto el campo a
girado 900 por lo que no pasa a través del polarizador y no habrá luz a la salida. Las
32
celdas no activadas son isótropas por lo que la luz que pasa por ellas sigue siendo lineal,
se refleja manteniéndose lineal y emerge a través del polarizador.
En la figura 4.7 se muestra en efecto del campo sobre un panel de moléculas de cristal
líquido.
Figura 4.7 Efecto de campo.
Figura 4.8 Se muestra un panel con los diferentes componentes: polarizadores, cristal
líquido y filtro de color para producir imágenes de color.
Figura 4.8 Panel con los diferentes componentes.
33
4.2.3 Diversidad de módulos LCD
Hay una gran variedad de versiones, clasificadas en dos grupos. En el primer grupo está
referido a los módulos LCD de caracteres (solamente se podrá presentar caracteres y
símbolos especiales en las líneas predefinidas en el módulo LCD) y el segundo se refiere
a módulos matriciales ( se podrán presentar caracteres, símbolos especiales y gráficos).
4.2.4 Tipos de memorias del LCD (Display Data RAM)
DD-RAM: Es la memoria encargada de almacenar los caracteres de la pantalla que se
están visualizando en ese momento. El display tiene una capacidad de 2 líneas
horizontales por 40 caracteres cada una, de los cuales sólo serán visibles 2 líneas de 16
caracteres cada una. La DD RAM tiene un tamaño de 2x40=90 bytes.
Una vez conocida la disposición de almacenamiento del display, es fácil pensar en un
display de 2 líneas de 40 caracteres sobre el que se desplaza una ventana de 2 líneas por
16 caracteres.
Figura 4.9 DD RAM (Display Data RAM).
El orden del cuadrante de los caracteres sería empezando de izquierda a derecha, de tal
modo que el carácter 1 sería l primero de la izquierda y el 40 sería el de la derecha. Para
localizar los caracteres se utilizan dos coordenadas (X, Y) siendo Y el valor vertical
34
entre 1 y 2 y X el valor horizontal (1-40) que indicará el carácter. En la figura anterior,
vemos la frase “alumnos de telemática EPSA”, pero en el display sólo muestra
“telemática EPSA” que corresponde a los 16 caracteres visibles. Para visualizar toda la
información en el display, podremos tratar al recuadro de 2 líneas por 16 caracteres
como si se tratara de una ventana móvil. Cuando se inicialice el LCD la pantalla tendría
un aspecto como lo muestra la figura 4.10.
Figura 4. 10 Ejemplo de DD RAM.
CG- RAM: Contiene los caracteres que pueden ser definidos por el usuario. Está
formada por 64 posiciones, con direcciones $00-$3F. Cada posición es de 5 bits. La
memoria está dividida en 8 bloques que corresponden a los posibles caracteres creados
por el usuario, que van del 0 al 7.
$00
$07
$08
$0F
$10
$17
$18
$1F
Carácter 0 $20
$27
Carácter 1 $28
$2F
Carácter 2 $30
$37
Carácter 3 $38
$3F
8
Carácter 4
Carácter 5
Carácter 6
Carácter 7
5 bits
Tabla 4.2 Caracteres creados por el usuario.
35
4.2.5 Características principales
Pantalla de caracteres ASCII, además de los caracteres Kanji y Griegos.
Desplazamiento de los caracteres hacia la izquierda o la derecha.
Proporciona la dirección de la posición absoluta o relativa del carácter.
Memoria de 40 caracteres por línea de pantalla.
Movimiento del cursor y cambio de su aspecto.
Permite una conexión a un procesador usando un interfaz de 4 u 8 bits el usuario pueda
programar 8 caracteres.
Para comunicarse con la pantalla LCD podemos hacerlo por medio de sus patitas de
entrada de dos maneras posibles, con bus de 4 bits o con bus de 8 bits, este último es el
que se explicará. En la siguientes figuras veremos las dos maneras posibles de
conexionar el LCD con un PIC16F84.
Figura 4.6 Conexionado con bus de 4 bits.
36
Figura 4.7 Conexionado con bus de 8 bits.
Como puede apreciarse el control de contraste se realiza al dividir la alimentación de 5V
con una resistencia variable de 10K.
Las líneas de datos son triestado, esto indica que cuando el LCD no está habilitado sus
entradas y salidas pasan a alta impedancia.
4.2.6 Descripción de pines
Los pines 1 y 2, son los utilizados para la alimentación del módulo LCD.
El pin 3 se utiliza para ajustar el contraste de la pantalla LCD. Por medio de un
potenciómetro
se regula la intensidad de los caracteres, a mayor tensión mayor
intensidad.
El pin 4 se utiliza para indicar al bus de datos si la información que le llega es una
instrucción o por lo contrario es un carácter. Si RS=0 indicara que en el bus de datos está
una instrucción, y si RS=1, indicara que tiene un carácter alfanumérico.
El pin 5 es el de escritura o lectura. Si RW=0 el módulo escribe en pantalla el dato que
haya en el bus de datos, y si RW=1 leerá lo que hay en el bus de datos.
El pin 6 es el indicado de hacer que el módulo LCD funcione, o por lo contrario no
acepte órdenes de funcionamiento. Cuando E=0 no se podrá utilizar el display y cuando
E=1 se podrán transferir datos y realizar las demás operaciones.
37
Pin #
1
2
3
Símbolo
Vss
Vdd
Vo
4
RS
5
R/W
6
E
7-14
D0-D7
Descripción
Tierra de alimentación GND
Alimentación de +5V CC
Contraste del cristal líquido. ( 0 a +5V )
Selección del registro de control/registro de datos:
RS=0 Selección registro de control
RS=1 Selección registro de datos
Señal de lectura/escritura:
R/W=0 Escritura (Write)
R/W=1 Lentura (Read)
Habilitación del módulo:
E=0 Módulo desconectado
E=1 Módulo conectado
Bus de datos bidireccional.
Tabla 4.3 Descripción de los pines del indicador digital (LCD).
4.2.7 Tensiones máximas
Descripción
Símbolo Mínima Máxima Unidad
Alimentación
VDD- VSS -0,3
+7
V
Tensión LCD
VLCD
-0,3
+13
V
Temperatura de operación TOP
0
+50
°C
Intervalo de temperatura
-20
+60
°C
TST
Tabla 4.4 Tensiones máximas del indicador digital (LCD).
4.2.8 Características eléctricas
Descripción
Símbolo
Alimentación (lógica) VDD-VSS
Alimentación (LCD)
VLCD
Entradas de
alimentación
VIH (VDD=5)
Alta
Baja VIL (VDD=5)
Mínima
Estándar Máxima
Unidad
4,5
5
5,5
V
-
4,7
-
V
-0,7 VDD
-
+0,3 VDD
V
-0,3
-
0,2 VDD
Corriente (lógica)
IDD (VDD-VSS=5)
-
1,6
-
mA
Corriente (LCD)
IEE
-
0,44
-
mA
Tabla 4.5 Características eléctricas del indicador digital (LCD).
38
4.3 Juegos de instrucciones
4.3.1 Comando de borrar DISPLAY ( LCD )
Borra el módulo LCD y coloca el cursor en la primera posición ( dirección 0). Pone el
bit I/D a 1 por defecto.
RS
R/W
DB7
DB6
DB5
DB4
DB3
DB2
DB1
DB0
Los datos que se lean o escriban posteriormente, lo hacen desde esta memoria CG RAM.
RS
0
R/W
0
DB7
0
DB6
1
DB5 DB4 DB3 DB2 DB1
DB0
Dirección de la CG RAM
Tiempo de ejecución: 40µS
4.3.2 Dirección de la memoria DD RAM
Los caracteres o datos que se van visualizando, se van almacenando en una memoria
llamada DD RAM para de aquí pasar a la pantalla.
Mediante esta instrucción se establece la dirección de la memoria
DD RAM a partir de la cual se irán almacenando los datos a visualizar. Ejecutando este
comando, todos los datos que se escriban o lean posteriormente lo harán desde esta
memoria DD RAM. Las direcciones de la 80h a la 8Fh corresponden con los 16
caracteres del primer renglón y de la C0h a la CFh con los 16 caracteres del segundo
renglón, para este modelo de LCD.
RS
0
R/W
0
DB7
1
DB6 DB5 DB4 DB3
Dirección de la DD RAM
DB2
DB1
DB0
39
4.3.3 Comando de lectura BUSY FLAG
Cuando el módulo LCD está ejecutando cualquiera de estas instrucciones, tarda un cierto
tiempo de ejecución en el que no se debe mandar ninguna instrucción. Para ello dispone
de un flag llamado BUSY (ocupado) que indica que se está ejecutando una instrucción
previa.
Esta instrucción de lectura informa del estado de dicho flag, además de proporcionar el
valor del contador de direcciones de la CG RAM o de la DD RAM, según la última que
se haya empleado.
RS
0
R/W
1
DB7
BF
DB6 DB5 DB4 DB3 DB2 DB1
DB0
Dirección de la CG RAM o DD RAM
4.3.4 Comando de escritura en la memoria CG O DD RAM
Mediante este comando se escribe en la memoria DD RAM los datos que se quieren
presentar en pantalla, y que serán los diferentes códigos ASCII de los caracteres a
visualizar.
Igualmente se escribe en la memoria CG RAM los diferentes bytes que permiten
confeccionar caracteres gráficos a gusto del usuario.
El escribir en uno u otro tipo de memoria depende de si se ha empleado previamente la
instrucción de direccionamiento DD RAM, o la de direccionamiento CG RAM.
RS
1
R/W
0
Código ASCII o byte del carácter gráfico
DB1
DB0
40
4.3.5 Comando de lectura de la memoria CG O DD RAM
Mediante este comando se lee de la memoria DD RAM los datos que haya almacenados
y que serán los códigos ASCII de los caracteres almacenados.
Igualmente se lee de la memoria CG RAM los diferentes bytes con los que se ha
confeccionado un determinado carácter gráfico.
El leer de uno u otro tipo de memoria depende de si se ha empleado previamente la
instrucción de direccionamiento de la DD RAM, o la de direccionamiento CG RAM.
RS
1
R/W
1
Código ASCII o byte del carácter gráfico
DB1
DB0
4.4 Esquema del PIC16F84
Figura 4.7 Descripción del PIC16F84.
41
4.4.1 Recursos fundamentales en el microcontrolador PIC16F84
Conjunto de únicamente 35 instrucciones.
Todas las instrucciones se hacen en un ciclo ( 400 ns a 10 MHz ), excepto para el
programa principal que son 2 ciclos.
Funcionamiento máximo: DC – 10 Hz en entrada de reloj.
DC – 400 ns en un ciclo de instrucción.
Dispositivo
Frecuencia
Memoria
Máx.
Dato
Flash
CR = ROM RAM EEPROM
PIC16F84
1k
68
64
10 MHz
Instrucciones de 14 bits de longitud.
Datos de 8 bits de longitud.
Un registro de 15 funciones especiales para el Hardware.
Modos de dirección directa, indirecta y relativa.
4 fuentes de interrupción:
-
Pin externo RB0/INT.
-
Desbordamiento del timer 0.
-
Cambio sobre la interrupción PROTB <7:4>.
-
Escritura de dato completo de la EEPROM.
Una memoria EEPROM de 1,000,000 ciclos, escritura/borrado de datos.
Retención de datos (EEPROM) > 40 años.
4.4.2 Características periféricas
13 pines I/O con dirección de control individual.
Alta corriente
Máximo 25 mA para sink.
42
Máximo 20 mA para la fuente.
Timer 0: conteo de tiempo de 8 bits y 8 bits para programar el prescalador.
4.4.3 Características especiales para el microcontrolador
Reset al encendido (POR).
Tiempo de encendido (PWRT).
Iniciar hacia el oscilador del timer (OST).
Perro guardián (WDT) con su propio oscilador “on-chip” RC para rehabilitar esta
operación.
Código de protección.
Modo SLEEP.
0pciones selectibles del oscilador.
Programable vía serial en 2 pines (dispositivo de soporte ROM y datos programados en
EEPROM).
4.4.4 Tecnología CMOS
Baja-potencia, alta-velocidad, tecnología CMOS flash/EEPROM.
Rangos de tensión de operación:
-
Comercial: 2 a 6 V.
-
Industrial: 2 a 6 V.
Bajo consumo:
-
Típico < 2 mA a 5 V, 4 MHz.
-
Consumo típico de corriente < 1 uA a 2 V.
-
Típico 15 uA a 2 V, 32 kHz.
43
4.4.5 Descripción general
El PIC16F84 pertenece a la familia PIC16CXX de bajo costo, alto desempeño, CMOS,
completamente estático, es un microcontrolador de 8 bits.
Todos los microcontroladores emplean un arquitectura avanzada RISC. Este dispositivo
PIC16CXX tiene, fuentes de interrupción múltiples, tanto internas como externas; es una
de sus características. La separación de la instrucción
y el bus de datos de la
arquitectura Harvard, deja una instrucción de 14 bits de longitud y un bus de datos de 8
bits. Los dos estados de instrucción paralela dejan que se ejecuten todas las instrucciones
en un ciclo, excepto para las instrucciones bifurcas (que requieren de 2 ciclos). El
microcontrolador PIC16F84 tiene un total de 35 instrucciones. Adicionalmente tiene un
largo conjunto de registros usados para un muy alto desempeño.
El típico microcontrolador PIC16F8X ejecuta un código de compresión a 2:1 y mejora la
velocidad a 2:1 (10 MHz), sobre otro microcontrolador clásico de 8 bits.
El PIC16F8X tiene hasta 68 bytes de RAM, 64 bytes de datos en la memoria EEPROM
y 13 pines I/O.
La familia PIC16CXX por características especiales reduce componentes externos,
costos, el consumo de potencia, y rehabilita el sistema. Estas son las 4 opciones del
oscilador: El oscilador RC suministra solución de bajo costo; el oscilador LP minimiza
el consumo de potencia; el XT es un cristal estándar, y el HS es para cristales de alta
velocidad. El modo sleep ofrece un bajo consumo de energía.
44
4.4.6 Descripción de pines
Tipo de
No. Tipo
buffer
de
De
pin I/O/P
OSC1/CLKIN
16
I
ST/CMOS
(3)
OSC2/CLKOUT 15
O
-
Descripción
Nombre de pin
MCRL
4
I/P
ST
RA0
RA1
RA2
RA3
RA4/TOCKI
RB0/INT
RB1
RB2
RB3
RB4
RB5
RB6
RB7
17
18
1
2
3
6
7
8
9
10
11
12
13
I/O
I/O
I/O
I/O
I/O
I/O
I/O
I/O
I/O
I/O
I/O
I/O
I/O
VSS
5
P
TTL
TTL
TTL
TTL
ST
TTL/ST
(1)
TTL
TTL
TTL
TTL
TTL
TTL/ST
(2)
TTL/ST
(2)
-
VDD
14
P
-
Entrada del oscilador de cristal y
entrada de reloj de la fuente externa.
Salida del oscilador.Conecta y
desconecta el modo oscilador del
cristal. En el modo RC, la salida OSC2
en el pin CLKOUT, que tiene una
frecuencia de ¼ de OSC1 y denota las
instrucciones del ciclo.
Limpiar la entrada del programa y
entrada de tensión. Este pin activa el
dispositivo de reset.
El puerto A es bidireccional.
Puede ser seleccionado como entrada
del reloj del timer 0.
Salida abierta del tipo drain.
El puerto B es bidireccional I/O. El
puerto B puede ser programado en el
software para trabajar como entradas.
RB0/INT puede ser seleccionado como
interrupción externa.
Pin de interrupción o cambio.
Pin de interrupción o cambio.
Programado serial del reloj y datos.
Alimentación de referencia lógica para
los pines I/O (tierra).
Alimentación positiva lógica para los
pines I/O.
Tabla 4.6 Descripción de los pines del microcontrolador PIC16F84.
Nota
I = Entrada; O = Salida; - = No usado; P = Alimentación; TTL = TTL entrada y ST = Entrada Schmitt Trigger.
1: Este buffer es una entrada de Schmitt Trigger cuando es configurada una
interrupción externa.
2: Este buffer es una entrada de Schmitt Trigger cuando es usado el modo de progrmación serial.
3: Este buffer es una entrada de Schmitt Trigger cuando es configurado el modo oscilador RC y una entrada
distinta a cmos.
45
4.4.7 Set de 35 instrucciones
Las instrucciones tienen un tamaño de palabra de 14 bits, éstas se pueden clasificar en 5
grupos:
1.- Operaciones orientadas a manejar registros de tamaño byte
Sintaxis
ADD f, d
AND f, d
CLRF f
CLRW
COMF f, d
DECF f, d
INCF f, d
IORWF f, d
MOVF f, d
MOVWF f, d
NOP RLF f, d
RRF f, d
SUMWF f, d
SWAPF f, d
XOR f, d
Descripción
Sumar w con f
AND w con f
Borrar f
Borrar w
Complementar f
Decrementar f
Incrementar f
Or entre w y f
Mueve f a w
Mueve w a f
No operación
Rota f a la izquierda
Rota f a la derecha
Resta w a f
Intercambiar nibbles
XOR de w
Ciclos
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
Señalizadores
C, DC, Z
Z
Z
Z
Z
Z
Z
Z
Z
Z
C
C
C, DC ,Z
Z
Tabla 4.7 Registros de tamaño byte.
2.- Operaciones orientadas a manejar bits.
Sintaxis Descripción
Ciclos Señalizadores
BCF f, b Borra el bit “b” del 1
registro “f”
BSF f, b Pon un “1” al bit “b” 1
del registro “f”
Tabla 4.8 Operaciones orientadas a manejar bits.
46
3.- Operaciones que manejan valores inmediatos.
Sintaxis
ADDLW k
ANDLW k
IORLW k
MOVLW k
SUBLW k
XORLW k
Descripción
Suma inmediatamente con w
AND inmediatamente con w
Or inmediatamente con w
Mover w a un valor inmediato
Restar w de un valor inmediato
Or exclusiva de valor inmediato
con w
Ciclos
1
1
1
1
1
1
Señalizadores
C, DC ,Z
Z
Z
C, DC ,Z
Z
Tabla 4.9 Operaciones que manejan valores inmediatos.
4.- Operaciones especiales y de control de flujo del programa.
Sintaxis
CALL k
CLRWDT k
GOTO k
RETFIE k
RETLW k
RETUR k
SLEEP k
Descripción
Llamar a subrutina
Borra o regresa al WDT
Salto incondicional
Retorno de interrupción con GIE=1
Retorno de etiqueta y carga w con k
Retorno de subrutina
Pasa al modo de reposo
Ciclos
1ó2
1
2
2
2
2
1
Señalizadores
-
Tabla 4.10 Operaciones especiales.
5.- Operaciones de salto condicional.
Sintaxis
BTFSC f, d
Descripción
Checa el bit “b” del registro
“f” y brinca si es 0
BTFSS f, d Checa el bit “b” del registro
“f” y brinca se es 1
DECFSZ f, d Decrementa el registro f y
brinca si es 0
INCFSZ f, d Incrementa el registro f y
brinca si es 0
Ciclos Señalizadores
1ó2 1ó2
-
1ó2
-
1ó2
-
Tabla 4.11 Operaciones de salto condicional.
47
CAPÍTULO V
DESARROLLO DEL
PROYECTO
48
5.1 Antecedentes
El proyecto encomendado consistió en implementar un indicador digital (LCD) a una
máquina envasadora de bolis. La principal función de este sería mostrar en la pantalla de
cristal líquido el modo de operación en el que se encuentra la
máquina, ya sea
automático, semiautomático o automático doble. Para lo cual se necesitaba tener
conocimiento acerca de microcontroladores, ya que por medio de este componente
electrónico se hace funcionar el indicador digital, para que mostrara en su pantalla en
qué modo de operación se encuentra la máquina envasadora de bolis. También se
requirió de tener conocimientos acerca del software MPLAB para programar este tipo
de microcontroladores, ya que es la manera por la cual se hará que funcione el
microcontrolador y hacer que el indicador digital opere.
Posteriormente se prosiguió a investigar los fundamentos de los componentes ya
mencionados, desde cómo funcionan, cuáles son sus parámetros de trabajo y las
aplicaciones que pueden desempeñar.
A continuación se menciona cómo se implementó el indicador digital (LCD) a la
máquina envasadora de bolis. Los componentes que se utilizarán en la máquina
envasadora de bolis serán algunos de sus botones que mandarán el pulso al
microcontrolador para mostrar en qué modo de operación se encuentra la máquina.
5.2 Elaboración de una fuente de 5 V
Al principio se tenía en cuenta alimentar el sistema mínimo (circuito electrónico) del
microcontrolador, con un circuito temporizador que está dentro de la máquina. Pero
como el microcontrolador (PIC16F84) opera con una tensión de 5 V, no es alcanzada
por el temporizador, ya que es de una tensión de 3 V. Por ello se llegó a la conclusión
de realizar una fuente de 5 V fija. El primer paso fue realizar el diagrama eléctrico
(figura 5.1), después se hizo una cotización de los componentes eléctricos que integran
la fuente de 5 V, los cuales son: transformador 120 V a 6 V a ½ A, una clema,
49
resistencia de 470 ohms, un led, capacitor electrolítico 1000 uf a 25 V y 10 uf a 16 V, un
LM7805, puente retificador UTL 2W04M y una tarjeta. Una vez comprado todo el
material, se pasó el diagrama eléctrico al programa OrCAD. Se imprimió y se mandó a
serigrafiar. La principal función de la fuente de 5 V es la de alimentar al sistema mínimo
del microcontrolador (PIC16F84), ya que éste requiere de una tensión de 5 V para su
funcionamiento.
Figura 5.1 Diagrama eléctrico de la fuente de 5 V.
5.2.1
Ensamble de componentes en la tarjeta
Para la construcción de la tarjeta, los componentes electrónico no llevan un determinado
orden para su ensamble, pero se recomienda que se construya por módulos y que si en
alguno se produce un falla sea fácil detectarla para solucionarla.
5.3 Elaboración del circuito electrónico del microcontrolador (PIC16F84)
Se diseñó el diagrama eléctrico (figura 5.2) del microcontrolador (PIC16F84). Antes de
llegar hacer el circuito electrónico impreso para el microcontrolador, primero se tuvo
50
que realizar un diagrama eléctrico con los componentes electrónicos que debe llevar el
microcontrolador (PIC16F84) para su funcionamiento, los cuales son los siguientes: Un
cristal XT 4 MHz, 2 capacitores de 22 pf, una resistencia de 10 kilo ohms, un botón
pulsador (reset), una clema y una tira de pines. Ésta última se utilizó para tener
comunicación con el indicador digital (LCD). Una vez diseñado el diagrama eléctrico, se
pasó al programa OrCAD para darle una mejor presentación y cuando se terminó se
imprimió. Después se mandó a serigrafiar.
Figura 5.2 Diagrama eléctrico del PIC16F84.
5.3.1 Ensamble de los componentes en la tarjeta
Para la construcción de la tarjeta, los componentes no llevan un determinado orden en su
ensamblaje, pero si algún día se produce una falla se debe detectar para solucionarla.
Todos los componentes son comerciales, el único que puede ocasionar problemas es el
integrado PIC16F84, ya que se consigue por lo regular sobre pedido.
51
Se recomienda revisar más de dos veces los valores y configuración de todos los
componentes, antes de instalarlos y soldarlos en la tarjeta. Para el circuito integrado
conviene usar bases zócalo para evitar problemas o daños con lo caliente del cautín. La
tarjeta tendrá dos puertos (A y B) que se ocuparán como entrada y salida: como entrada
el puerto A y como salida el puerto B. En el puerto B se conectará el indicador digital
(LCD).
5.4 Programa para el microcontrolador PIC16F84
El MPLAB es un software que junto con un emulador y un programador, forman un
conjunto de herramientas de desarrollo muy completo para el trabajo o diseño con los
microcontroladores (PIC). Además incorpora todas las utilidades necesarias para la
realización de cualquier proyecto y, para los que no disponen de un emulador, el
programa permite editar el archivo fuente en lenguaje ensamblador de nuestro proyecto,
además de ensamblarlo y simularlo en pantalla, pudiendo ejecutarlo paso a paso y ver
como evolucionarían de forma real sus registros internos.
El programa en sí es una serie de comandos que se escriben en lenguaje ensamblador
dentro del software MPLAB, compatibles con los comandos del microcontrolador
(PIC16F84). Y estas instrucciones hacen varias condiciones para mostrar ciertas
palabras en el indicador digital (LCD). Esto se debe a que cuando el microcontrolador
despliega estas instrucciones, ya no lo hace en lenguaje ensamblador si no en leguaje
máquina, el cual permite ver esas palabras en el LCD.
El software para realizar el programa del microcontrolador es el MPLAB. Su principal
función será grabar el programa dentro del microcontrolador, para que éste despliegue
ciertas condiciones en el indicador digital (LCD) que son los modos de operación en que
se encuentra la máquina. Para verificar que el programa era correcto, se realizaron unas
pruebas con el PIC16F873A, programándolo y utilizando el sistema mínimo realizado
en la escuela. Para simular los botones que mandan pulsos desde de la máquina
envasadora, se utilizo un dip-switch; una vez terminada esta prueba, se fue a recoger la
52
tarjeta serigrafiada, para después empezar a realizar pruebas con el microcontrolador
PIC16F84.
Inicio
Compara
No
No
Si es
con1
Si
Hacer
rutina con1
Llamar subrutina
de tabla de datos
Mostrar
nombre
Si es
con2
Si no es con2
y con1
Si
Hacer
rutina con2
Llamar subrutina
de tabla de datos
Mostrar
nombre
Hacer
Rutina con3
Llamar subrutina
de tabla de datos
Mostrar
nombre
Fin
5.1 Diagrama de flujo del programa.
53
5.4 Reductor de tensión
La función del reductor de tensión es controlar la tensión de los botones de la máquina.
Debido a que la tensión de la máquina envasadora de bolis era de 127 VAC, y el
microcontrolador utilizado opera con una tensión de sólo 5V, se desarrollo un reductor
de tensión, con la ayuda del asesor de la empresa.
1.- Se diseño el diagrama eléctrico, que contiene los siguientes componentes: un
relevador 127 AC.
2.- Se realizarán algunas pruebas en proto board.
3.- Se diseñó en OrCAD.
4.- Se mandó a serigrafiar.
Figura 5.3 Diagrama eléctrico del reductor de tensión.
5.6 Ensamble de las tarjetas en la máquina envasadora de bolis
1.- Por último se realizó el ensamble de la tarjetas dentro de la máquina envasadora de
bolis.
2.- Antes del ensamblado se tuvo que realizar un orificio en el panel de control de la
máquina para la colocación del indicador digital.
3.- Después se instalaron las tarjetas tanto del microcontrolador, como la del reductor de
tensión y la de la fuente.
4.- Pero antes se colocaron éstas dentro de una caja de plástico, para una mejor
protección dentro de la máquina.
5.- Y por último se realizó el cableado de las tarjetas, las cuales no tienen un orden para
empezar hacerlo.
54
5.6.1 Cableado en la máquina envasadora de bolis
La alimentación de corriente alterna se toma del circuito temporizador que esta dentro de
la máquina envasadora de bolis.
Figura 5.4 Diagrama de conexión del indicador digital (LCD) en la máquina envasadora
de bolis.
55
CAPÍTULO VI
EVALUACIÓN
ECONÓMICA
56
6.1 Evaluación económica
El costo del proyecto ya terminado no fue muy caro para la empresa, ya que muchos de
los componentes que se incluyeron dentro de las tarjetas electrónicas utilizadas son
comerciales. Para que se tenga una idea más clara sobre el monto del proyecto, se
presenta a continuación la lista del material que se ocupó, así como el costo de cada
componente.
Lista de material para el sistema mínimo para el control del indicador digital (LCD).
Material
Costo
LCD (TM162AAA).
$135
PIC16F84.
$67
Botón pulsador.
$2
Resistencia 10 k.
$.25
Cristal XT 4 MHz.
$10
2 Capacitores 22 pf.
$2
Tira de terminales sencilla.
$1.50
Resistencia multivueltas (Trimpot) 10 k.
$10
Clema.
$2.50
Conectores 2x8
$10
Tarjeta
$10
Tarjeta serigrafiada
$30
TOTAL
$280.25
Tabla 6.1 Costos del material para el sistema mínimo.
57
Lista de material para la fuente de 5 V.
Material
Costo
Transformador 120/6V.
$25.50
Clema.
$2.50
Led.
$1
LM7805.
$3.50
Capacitor electrolítico 1000 uf a 25 V. $2.50
Capacitor electrolítico 10 uf a 16 V.
$1
Puente rectificador UTL(2w04m).
$3
Tarjeta.
$10
Tarjeta serigrafiada.
$30
TOTAL
$79
Tabla 6.2 Lista de material para fuente de 5 volts.
Lista de material para el reductor de tensión.
Material
Costo
Relevador 127 AC $20
Tarjeta
$10
Tarjeta serigrafiada $30
TOTAL
$60
Tabla 6.3 Lista de material para el reductor de tensión.
58
CAPÍTULO VII
RESULTADOS
OBTENIDOS
59
7.2 Resultados cumplidos
De los alcances enumerados en el capítulo dos, el primero no se llevó acabo al 100 %,
ya que no se concluyó el proyecto en el tiempo previsto. Esto se debió a que la mayor
parte de la estadía se ocupó en la realización de diversas actividades dentro de la
empresa, que sólo permitieron alcanzar el 70% del objetivo.
El segundo alcance, consistente en entregar las tarjetas al asesor de empresa, tampoco se
logró, por no saber utilizar totalmente el programa OrCAD, el cual me habría permitido
realizar los diagramas eléctricos y a su vez pasarlos a PCB para luego mandarlos a
serigrafiar.
El tercer alcance, hacer pruebas con el sistema mínimo, si se cumplió ya que se
realizaron varias pruebas en proto board, como en el sistema mínimo realizado en la
escuela.
El cuarto alcance, también se cumplió, ya que se hizo lo posible por dejarle toda la
información al cliente acerca del microcontrolador y el indicador digital, así como sus
hojas de datos principales.
El quinto alcance también se logró, obteniendo un proyecto muy económico. Por ello, se
buscaron varios precios sobre los componentes que llevarían el sistema mínimo
(microcontrolador), la fuente de 5 V y el reductor de tensión, para una reducción de
costos para la empresa.
60
CONCLUSIONES
61
CONCLUSIÓN
En el ámbito de la teoría, la realización de este proyecto me enseño que no es fácil, la
programación de los microcontroladores si no se conoce el manejo del software
MPLAB. Además el enfrentar esta dificultad me permitió descubrir y aprovechar la
abundante información que existe sobre el tema, lo cual me permitió seguir adelante .
Los microcontroladores son una herramienta que actualmente se está utilizando en la
mayoría de las empresas. Mi experiencia directa con esta realidad dentro de la empresa
en la que se realizó el presente trabajo, me hizo tomar conciencia de la necesidad de
conocer directamente los avances tecnológicos y sus aplicaciones prácticas, en orden o
poder completar la formación académica recibida en la escuela.
62
BIBLIOGRAFÍA
63
BIBLIOGRAFÍA
http://usuarios.lycos.es/sfriswolker/pic/uno.htm (MICROTROLADOR).
http://www.tianma.com/spec_sheets/TM162Aaa.PDF (LCD).
http://www.ucm.es/info/opticaf/Lecciones_virtuales/polarizacion/medios_anisotropos/ap
lica2cristal_9.htm (CRISTALES LÍQUIDOS).
http://server-die.alc.upv.es/asignaturas/LSED/2002-03/Pantallas_LCD/LCD.pdf
http://www.microchip.com/download/lit/pline/picmicro/families/16f8x/30430c.pdf
(PIC16F84).
64
ANEXOS
65
Programa del microcontrolador
;Programa: Modos.asm
;Función: Utilización de rutinas para control de un LCD.
;Igualdades.
list p=16f84
;procesador PIC16f84
list c= 132
;listado a 132 caracteres
TIMER0
equ 01
;registro del TIMER0
OPCION
equ 0x1
;registro de opciones pagina 1
PCL
equ 0x2
;registro PC
PCLATH
equ 0xa
;registro alto del PC
STATUS
equ 03
;registro de estado
RA
equ 05
;puerto A
RB
equ 06
;puerto B
PORTA
equ 05
;puerto A
PORTB
equ 06
;puerto B
TRISA
equ 85h
;registro de programación del puerto A pagina 1
TRISB
equ 86h
;registro de programación del puerto B pagina 1
INTCON
equ 0xb
;registro de control de interrupciones
DATO_A
equ 0xc
;registro del dato A
DATO_B
equ 0xd
;registro del dato B
RESUL
equ 0xe
;registro de resultados
TEMPO1
equ 0xf
;registro temporal 1
TEMPO2
equ 0x10
;registro temporal 2
FOCET
equ 0x11
;variable de desplazamiento de mensajes
RP0
equ 05h
;bit 5 registro STATUS
DIGITO
equ 1Fh
;cursor para leer la tabla de datos
;Vector de reset
Org
00h
Goto
INICIO
Org
05h
;dirección del vector de reset
;comienza el programa
;detrás del vector de interrupción
Include”LCD.LIB”
; Programa: LCD.LIB
; Librería de funciones para controlar un display LCD 2x16.
LCD_E
BSF
NOP
BCF
RETURN
LCD_BUSY BSF
BSF
MOVLW
RA,2
RA,2
RA,1
STATUS,5
0xFF
;activa señal E del módulo LCD
;espera 1us
;desactiva señal E del módulo LCD
;pone el LCD en modo de lectura
;selecciona el banco 1
66
MOVWF
BCF
BSF
NOP
L_BUSY
BTFSC
Goto
BCF
BSF
CLRF
BCF
BCF
RETURN
LCD_REG BCF
MOVWF
CALL
Goto
LCD_DATOS BCF
MOVWF
CALL
BSF
Goto
LCD_INI
MOVLW
CALL
CALL
MOVLW
CALL
CALL
MOVLW
CALL
CALL
RETURN
LCD_PORT BSF
CLRF
MOVLW
MOVWF
BCF
; MOVLW b'00000000'
; MOVWF
INTCON
BCF
BCF
TRISB
STATUS,5
RA,2
;puerto B actúa de entrada
;activa el LCD (señal E)
RB,7
L_BUSY
RA,2
STATUS,5
TRISB
STATUS,5
RA,1
;checa el bit BUSY
;esta “1”
;desactiva el LCD (señal E)
;puerto B actúa como salida
;pone el LCD en modo de escritura
RA,0
RB
LCD_BUSY
LCD_E
RA,0
RB
LCD_BUSY
RA,0
LCD_E
b'00111000'
LCD_REG
DELAY_5ms
b'00111000'
LCD_REG
DELAY_5ms
b'00111000'
LCD_REG
DELAY_5ms
;desactiva RS (modo instrucción)
;saca el código de instrucción
;espera a que se libere el LCD
;genera pulso en señal E
;desactiva RS (modo instrucción)
;valor ASCII a sacar por RB
;espera a que se libere el LCD
;activa RS (modo dato)
;genera pulso en señal E
; w=00111000
;código de instrucción
;temporiza 5 ms
;w=00111000
;temporiza 5 ms
;w=00111000
;temporiza 5 ms
STATUS,5
TRISB
b'00011000'
TRISA
STATUS,5
;selecciona el banco 1 de datos
;RB se programa como salida
;w=00011000, RA<4:3> como entradas
;RA <2:0> se programan como salidas
;selecciona el banco 0 de datos
RA,0
RA,2
;desactiva interrupciones
;desactiva RS del módulo LCD
;desactiva E del módulo LCD
;DELAY_5MS genera una temporización de 5MS necesario para la secuencia
;de inicio del LCD.
DELAY_5ms MOVLW 0x1a
67
MOVWF
DATO_B
CLRF
DATO_A
DELAY_1 DECFSZ DATO_A,1
Goto
DELAY_1
DECFSZ
DATO_B,1
Goto
DELAY_1
RETURN
;Inicio de programa principal en esta rutina se hace la comparación
INICIO
compara
call
btfsc
goto
call
btfsc
goto
call
goto
goto
inicia
PORTA,3
con1
inicia
PORTA,4
con2
inicia
con3
compara
con1
MOVF
CALL
IORLW
BTFSC
goto
CALL
INCF
Goto
DIGITO,w
DATO_1
0
STATUS,2
ciclo
LCD_DATOS
DIGITO,f
con1
btfss
goto
goto
PORTA,3
compara
ciclo
MOVF
CALL
IORLW
BTFSC
goto
CALL
INCF
Goto
DIGITO,w
DATO_2
0
STATUS,2
ciclo
LCD_DATOS
DIGITO,f
con2
;w=DIGITO
;escoge el caracter
;compara
;es el último
;si
;visualizar caracter
;incrementa número DIGITO
;vuelve a escribir
ciclo
con2
;w=DIGITO
;escoge el caracter
;compara
;es el último
;si
;vuelve a escribir
68
ciclo1
btfss
goto
goto
PORTA,4
compara
ciclo1
con3
MOVF
CALL
IORLW
BTFSC
goto
CALL
INCF
Goto
DIGITO,w
DATO_3
0
STATUS,2
ciclo
LCD_DATOS
DIGITO,f
con3
;w=DIGITO
;escoge el caracter
;compara
;es el último
;si
;vuelve a escribir
ciclo2
btfsc
goto
btfsc
goto
goto
PORTA,3
compara
PORTA,4
compara
ciclo2
; declaración de subrutinas para elegir la tabla de datos
inicia
CLRF
DIGITO
;pone a 0 la variable DIGiTO
CALL
LCD_PORT
;puertos en modo LCD
BCF
RA,0
;desactiva RS del módulo LCD
BCF
RA,2
;desactiva E del módulo LCD
START CALL
LCD_INI
;inicia LCD (CFG puertos)
START_1 MOVLW b'0000000'
;borrar LCD
CALL
LCD_REG
MOVLW
b'00000110'
;w=00000110
CALL
LCD_REG
MOVLW
b'00001100'
;w=00001100,LCD encendido y apagado
CALL
LCD_REG
MOVLW
0x80
;w=0x80, dirección caracter
CALL
LCD_REG
RETURN
;Tabla de datos
DATO_1
ADDWF PCL,1
RETLW 'A'
RETLW 'U'
RETLW 'T'
69
RETLW 'O'
RETLW 'M'
RETLW 'A'
RETLW 'T'
RETLW 'I'
RETLW 'C'
RETLW 'O'
RETLW 0x00
DATO_2
ADDWF PCL,1
RETLW 'S'
RETLW 'E'
RETLW 'M'
RETLW 'I'
RETLW 'A'
RETLW 'U'
RETLW 'T'
RETLW 'O'
RETLW 'M'
RETLW 'A'
RETLW 'T'
RETLW 'I'
RETLW 'C'
RETLW 'O'
RETLW 0x00
DATO_3
ADDWF PCL,1
RETLW 'A'
RETLW 'U'
RETLW 'T'
RETLW 'O'
RETLW 'M'
RETLW 'A'
RETLW 'T'
RETLW 'I'
RETLW 'C'
RETLW 'O'
RETLW ' '
RETLW 'D'
RETLW 'O'
RETLW 'B'
RETLW 'L'
RETLW 'E'
RETLW 0x00
end
70
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PIC16F8X
8-Bit CMOS Flash/EEPROM Microcontrollers
Devices Included in this Data Sheet:
•
•
•
•
•
Pin Diagram
PIC16F83
PIC16CR83
PIC16F84
PIC16CR84
Extended voltage range devices available
(PIC16LF8X, PIC16LCR8X)
PDIP, SOIC
• Only 35 single word instructions to learn
• All instructions single cycle (400 ns @ 10 MHz)
except for program branches which are two-cycle
• Operating speed: DC - 10 MHz clock input
DC - 400 ns instruction cycle
•1
18
RA1
RA3
2
17
RA0
RA4/T0CKI
3
16
OSC1/CLKIN
MCLR
4
15
OSC2/CLKOUT
VSS
5
14
VDD
RB0/INT
6
13
RB7
RB1
7
12
RB6
RB2
8
11
RB5
RB3
9
10
RB4
PIC16F8X
PIC16CR8X
High Performance RISC CPU Features:
RA2
Memory
Device
Freq
Max.
Data
Flash
PIC16F83
512 words
PIC16CR83
512 words
PIC16F84
1 K-words
PIC16CR84
1 K-words
F = Flash; CR = ROM
RAM
EEPROM
36
36
68
68
64
64
64
64
Special Microcontroller Features:
10 MHz
10 MHz
10 MHz
10 MHz
•
•
•
•
•
•
14-bit wide instructions
8-bit wide data path
15 special function hardware registers
Eight-level deep hardware stack
Direct, indirect and relative addressing modes
Four interrupt sources:
- External RB0/INT pin
- TMR0 timer overflow
- PORTB<7:4> interrupt on change
- Data EEPROM write complete
• 1,000,000 data memory EEPROM
ERASE/WRITE cycles
• EEPROM Data Retention > 40 years
Peripheral Features:
• 13 I/O pins with individual direction control
• High current sink/source for direct LED drive
- 25 mA sink max. per pin
- 20 mA source max. per pin
• TMR0: 8-bit timer/counter with 8-bit
programmable prescaler
•
•
•
•
•
•
•
•
Power-on Reset (POR)
Power-up Timer (PWRT)
Oscillator Start-up Timer (OST)
Watchdog Timer (WDT) with its own on-chip RC
oscillator for reliable operation
Code-protection
Power saving SLEEP mode
Selectable oscillator options
Serial In-System Programming - via two pins
(ROM devices support only Data EEPROM
programming)
CMOS Technology:
• Low-power, high-speed CMOS Flash/EEPROM
technology
• Fully static design
• Wide operating voltage range:
- Commercial: 2.0V to 6.0V
- Industrial:
2.0V to 6.0V
• Low power consumption:
- < 2 mA typical @ 5V, 4 MHz
- 15 µA typical @ 2V, 32 kHz
- < 1 µA typical standby current @ 2V
 1996 Microchip Technology Inc.
DS30430B-page 1
This document was created with FrameMaker 4 0 4
PIC16F8X
Table of Contents
1.0
General Description ............................................................................................................................................ 3
2.0
PIC16F8X Device Varieties ................................................................................................................................ 5
3.0
Architectural Overview........................................................................................................................................ 7
4.0
Memory Organization ....................................................................................................................................... 11
5.0
I/O Ports............................................................................................................................................................ 21
6.0
Timer0 Module and TMR0 Register.................................................................................................................. 27
7.0
Data EEPROM Memory.................................................................................................................................... 33
8.0
Special Features of the CPU ............................................................................................................................ 37
9.0
Instruction Set Summary ...................................................................................................................................55
10.0 Development Support ........................................................................................................................................67
11.0 Electrical Characteristics for PIC16F83 and PIC16F84.................................................................................... 71
12.0 DC & AC Characteristics Graphs/Tables for PIC16F83 and PIC16F84 ........................................................... 83
13.0 Electrical Characteristics for PIC16CR83 and PIC16CR84...............................................................................85
14.0 DC & AC Characteristics Graphs/Tables for PIC16CR83 and PIC16CR84 ......................................................97
15.0 Packaging Information .......................................................................................................................................99
Appendix A: Feature Improvements .........................................................................................................................103
Appendix B: Compatibility.........................................................................................................................................103
Appendix C: What’s New ..........................................................................................................................................104
Appendix D: What’s Changed...................................................................................................................................104
Appendix E: PIC16C84 to PIC16F83/CR83 and PIC16F84/CR84 Conversion Considerations...............................104
Appendix F: PIC16/17 Microcontrollers ....................................................................................................................105
Index............................................................................................................................................................................ 115
PIC16F8X Product Identification System ....................................................................................................................121
To Our Valued Customers
We constantly strive to improve the quality of all our products and documentation. We have spent a great deal of
time to ensure that these documents are correct. However, we realize that we may have missed a few things. If you
find any information that is missing or appears in error, please use the reader response form in the back of this data
sheet to inform us. We appreciate your assistance in making this a better document.
DS30430B-page 2
PIC16F8X
1.0
GENERAL DESCRIPTION
The PIC16F8X is a group in the PIC16CXX family of
low-cost, high-performance, CMOS, fully-static, 8-bit
microcontrollers. This group contains the following
devices:
•
•
•
•
PIC16F83
PIC16CR83
PIC16F84
PIC16CR84
All PIC16/17 microcontrollers employ an advanced
RISC architecture. PIC16CXX devices have enhanced
core features, eight-level deep stack, and multiple
internal and external interrupt sources. The separate
instruction and data buses of the Harvard architecture
allow a 14-bit wide instruction word with a separate
8-bit wide data bus. The two stage instruction pipeline
allows all instructions to execute in a single cycle,
except for program branches (which require two
cycles). A total of 35 instructions (reduced instruction
set) are available. Additionally, a large register set is
used to achieve a very high performance level.
PIC16F8X microcontrollers typically achieve a 2:1
code compression and up to a 2:1 speed improvement
(at 10 MHz) over other 8-bit microcontrollers in their
class.
The PIC16F8X has up to 68 bytes of RAM, 64 bytes of
Data EEPROM memory, and 13 I/O pins. A
timer/counter is also available.
The PIC16CXX family has special features to reduce
external components, thus reducing cost, enhancing
system reliability and reducing power consumption.
There are four oscillator options, of which the single pin
RC oscillator provides a low-cost solution, the LP
oscillator minimizes power consumption, XT is a
standard crystal, and the HS is for High Speed crystals.
The SLEEP (power-down) mode offers power saving.
The user can wake the chip from sleep through several
external and internal interrupts and resets.
A highly reliable Watchdog Timer with its own on-chip
RC oscillator provides protection against software
lock-up.
The devices with Flash program memory allow the
same device package to be used for prototyping and
production. In-circuit reprogrammability allows the
code to be updated without the device being removed
from the end application. This is useful in the
development of many applications where the device
may not be easily accessible, but the prototypes may
require code updates. This is also useful for remote
applications where the code may need to be updated
(such as rate information).
Table 1-1 lists the features of the PIC16F8X, and
Appendix D: list the features of all of the Microchip
microcontrollers.
A simplified block diagram of the PIC16F8X is shown in
Figure 3-1.
The PIC16F8X fits perfectly in applications ranging
from high speed automotive and appliance motor
control to low-power remote sensors, electronic locks,
security devices and smart cards. The Flash/EEPROM
technology makes customization of application
programs (transmitter codes, motor speeds, receiver
frequencies, security codes, etc.) extremely fast and
convenient. The small footprint packages make this
microcontroller series perfect for all applications with
space limitations. Low-cost, low-power, high
performance, ease of use and I/O flexibility make the
PIC16F8X very versatile even in areas where no
microcontroller use has been considered before
(e.g., timer functions, serial communication, capture
and compare, PWM functions and co-processor
applications).
The serial in-system programming feature (via two
pins) offers flexibility of customizing the product after
complete assembly and testing. This feature can be
used to serialize a product, store calibration data, or
program the device with the current firmware before
shipping.
1.1
Family and Upward Compatibility
Those users familiar with the PIC16C5X family of
microcontrollers will realize that this is an enhanced
version of the PIC16C5X architecture. Please refer to
Appendix A: for a detailed list of enhancements. Code
written for PIC16C5X can be easily ported to the
PIC16F8X (Appendix B:).
1.2
Development Support
The PIC16CXX family is supported by a full-featured
macro assembler, a software simulator, an in-circuit
emulator, a low-cost development programmer and a
full-featured programmer. A “C” compiler and fuzzy
logic support tools are also available.
DS30430B-page 3
PIC16F8X
PIC16F8X FAMILY OF DEVICES
Clock
Memory
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er
m
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m
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es
s)
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ry
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TABLE 1-1:
Vo
g
lta
s
R
ge
a
ck
Pa
PIC16C84
10
—
1K
PIC16F84(1)
2.0-6.0 18-pin DIP, SOIC
10
1K
—
—
68
64
TMR0
4
13
PIC16CR84(1)
10
—
—
1K
68
64
TMR0
4
13
PIC16F83(1)
10
512
—
—
36
64
TMR0
4
13
PIC16CR83(1)
10
—
—
512
36
64
TMR0
4
13
All PIC16/17 family devices have Power-on Reset, selectable Watchdog Timer, selectable code protect, and
high I/O current capability.
All PIC16C8X family devices use serial programming with clock pin RB6 and data pin RB7.
Note 1: Please contact your local sales office for availability of these devices.
DS30430B-page 4
PIC16F8X
2.0
PIC16F8X DEVICE VARIETIES
A variety of frequency ranges and packaging options
are available. Depending on application and production
requirements the proper device option can be selected
using the information in this section. When placing
orders, please use the “PIC16F8X Product
Identification System” at the back of this data sheet to
specify the correct part number.
There are four device “types” as indicated in the device
number.
1.
2.
3.
4.
F, as in PIC16F84. These devices have Flash
program memory and operate over the standard
voltage range.
LF, as in PIC16LF84. These devices have Flash
program memory and operate over an extended
voltage range.
CR, as in PIC16CR83. These devices have
ROM program memory and operate over the
standard voltage range.
LCR, as in PIC16LCR84. These devices have
ROM program memory and operate over an
extended voltage range.
When discussing memory maps and other architectural
features, the use of F and CR also implies the LF and
LCR versions.
2.1
Electrically Erasable Devices
These devices are offered in the lower cost plastic
package, even though the device can be erased and
reprogrammed. This allows the same device to be used
for prototype development and pilot programs as well
as production.
A further advantage of the electrically erasable version
is that they can be erased and reprogrammed in-circuit,
or by device programmers, such as Microchip's
PICSTART Plus or PRO MATE II programmers.
2.2
Quick-Turnaround-Production (QTP)
Devices
Microchip offers a QTP Programming Service for
factory production orders. This service is made
available for users who choose not to program a
medium to high quantity of units and whose code
patterns have stabilized. The devices have all Flash
locations and configuration options already programmed by the factory. Certain code and prototype
verification procedures do apply before production
shipments are available.
For information on submitting a QTP code, please
contact your Microchip Regional Sales Office.
2.3
Serialized
Quick-Turnaround-Production
(SQTP SM ) Devices
Microchip offers the unique programming service
where a few user-defined locations in each device are
programmed with different serial numbers. The serial
numbers
may
be
random,
pseudo-random
or sequential.
Serial programming allows each device to have a
unique number which can serve as an entry-code,
password or ID number.
For information on submitting a SQTP code, please
2.4
ROM Devices
Some of Microchip’s devices have a corresponding
device where the program memory is a ROM. These
devices give a cost savings over Microchip’s traditional
user programmed devices (EPROM, EEPROM).
ROM devices (PIC16CR8X) do not allow serialization
information in the program memory space. The user
may program this information into the Data EEPROM.
For information on submitting a ROM code, please
DS30430B-page 5
PIC16F8X
NOTES:
DS30430B-page 6
PIC16F8X
3.0
ARCHITECTURAL OVERVIEW
The high performance of the PIC16CXX family can be
attributed to a number of architectural features
commonly found in RISC microprocessors. To begin
with, the PIC16CXX uses a Harvard architecture. This
architecture has the program and data accessed from
separate memories. So the device has a program
memory bus and a data memory bus. This improves
bandwidth over traditional von Neumann architecture
where program and data are fetched from the same
memory (accesses over the same bus). Separating
program and data memory further allows instructions to
be sized differently than the 8-bit wide data word.
PIC16CXX opcodes are 14-bits wide, enabling single
word instructions. The full 14-bit wide program memory
bus fetches a 14-bit instruction in a single cycle. A
two-stage pipeline overlaps fetch and execution of
instructions
(Example 3-1).
Consequently,
all
instructions execute in a single cycle (400 ns @
10 MHz) except for program branches.
The PIC16F83 and PIC16CR83 address 512 x 14 of
program memory, and the PIC16F84 and PIC16CR84
address 1K x 14 program memory. All program memory is internal.
PIC16CXX devices contain an 8-bit ALU and working
register. The ALU is a general purpose arithmetic unit.
It performs arithmetic and Boolean functions between
data in the working register and any register file.
The ALU is 8-bits wide and capable of addition,
subtraction, shift and logical operations. Unless
otherwise mentioned, arithmetic operations are two's
complement in nature. In two-operand instructions,
typically one operand is the working register
(W register), and the other operand is a file register or
an immediate constant. In single operand instructions,
the operand is either the W register or a file register.
The W register is an 8-bit working register used for ALU
operations. It is not an addressable register.
Depending on the instruction executed, the ALU may
affect the values of the Carry (C), Digit Carry (DC), and
Zero (Z) bits in the STATUS register. The C and DC bits
operate as a borrow and digit borrow out bit,
respectively, in subtraction. See the SUBLW and SUBWF
instructions for examples.
A simplified block diagram for the PIC16F8X is shown
in Figure 3-1, its corresponding pin description is
shown in Table 3-1.
The PIC16CXX can directly or indirectly address its
register files or data memory. All special function
registers including the program counter are mapped in
the data memory. An orthogonal (symmetrical)
instruction set makes it possible to carry out any operation on any register using any addressing mode. This
symmetrical nature and lack of ‘special optimal
situations’ make programming with the PIC16CXX
simple yet efficient. In addition, the learning curve is
reduced significantly.
DS30430B-page 7
PIC16F8X
FIGURE 3-1:
PIC16F8X BLOCK DIAGRAM
13
Flash/ROM
Program
Memory
PIC16F83/CR83
512 x 14
PIC16F84/CR84
1K x 14
Data Bus 8
Program Counter
8 Level Stack
(13-bit)
Program
Bus 14
EEPROM Data Memory
RAM
File Registers
PIC16F83/R83/84
36 x 8
PIC16F84/CR84
68 x 8
7
EEDATA
RAM Addr
EEPROM
Data Memory
64 x 8
EEADR
Addr Mux
Instruction reg
5
7
Direct Addr
Indirect
Addr
TMR0
FSR reg
RA4/T0CKI
STATUS reg
8
MUX
Power-up
Timer
Instruction
Decode &
Control
Timing
Generation
Oscillator
Start-up Timer
I/O Ports
ALU
Power-on
Reset
Watchdog
Timer
RA3:RA0
W reg
RB7:RB1
RB0/INT
OSC2/CLKOUT
OSC1/CLKIN
DS30430B-page 8
MCLR
VDD, VSS
PIC16F8X
TABLE 3-1:
PIC16F8X PINOUT DESCRIPTION
DIP
No.
SOIC
No.
I/O/P
Type
OSC1/CLKIN
16
16
I
OSC2/CLKOUT
15
15
O
—
Oscillator crystal output. Connects to crystal or resonator in crystal
oscillator mode. In RC mode, OSC2 pin outputs CLKOUT which
has 1/4 the frequency of OSC1, and denotes the instruction cycle
rate.
MCLR
4
4
I/P
ST
Master clear (reset) input/programming voltage input. This pin is an
active low reset to the device.
RA0
17
17
I/O
TTL
RA1
18
18
I/O
TTL
RA2
1
1
I/O
TTL
RA3
2
2
I/O
TTL
RA4/T0CKI
3
3
I/O
ST
Pin Name
Buffer
Type
Description
ST/CMOS (3) Oscillator crystal input/external clock source input.
PORTA is a bi-directional I/O port.
Can also be selected to be the clock input to the TMR0
timer/counter. Output is open drain type.
PORTB is a bi-directional I/O port. PORTB can be software programmed for internal weak pull-up on all inputs.
RB0/INT
6
6
I/O
TTL/ST (1)
RB1
7
7
I/O
TTL
RB2
8
8
I/O
TTL
RB3
9
9
I/O
TTL
RB4
10
10
I/O
TTL
RB0/INT can also be selected as an external interrupt pin.
Interrupt on change pin.
RB5
11
11
I/O
TTL
RB6
12
12
I/O
TTL/ST (2)
Interrupt on change pin.
RB7
13
13
I/O
TTL/ST (2)
VSS
5
5
P
—
Ground reference for logic and I/O pins.
VDD
14
14
P
—
Positive supply for logic and I/O pins.
Interrupt on change pin. Serial programming clock.
Interrupt on change pin. Serial programming data.
Legend: I= input
O = output
I/O = Input/Output
P = power
— = Not used
TTL = TTL input
ST = Schmitt Trigger input
Note 1: This buffer is a Schmitt Trigger input when configured as the external interrupt.
2: This buffer is a Schmitt Trigger input when used in serial programming mode.
3: This buffer is a Schmitt Trigger input when configured in RC oscillator mode and a CMOS input otherwise.
DS30430B-page 9
PIC16F8X
Clocking Scheme/Instruction Cycle
3.1
3.2
The clock input (from OSC1) is internally divided by
four to generate four non-overlapping quadrature
clocks namely Q1, Q2, Q3 and Q4. Internally, the
program counter (PC) is incremented every Q1, the
instruction is fetched from the program memory and
latched into the instruction register in Q4. The
instruction is decoded and executed during the
following Q1 through Q4. The clocks and instruction
execution flow is shown in Figure 3-2.
Instruction Flow/Pipelining
An “Instruction Cycle” consists of four Q cycles (Q1,
Q2, Q3 and Q4). The instruction fetch and execute are
pipelined such that fetch takes one instruction cycle
while decode and execute takes another instruction
cycle. However, due to the pipelining, each instruction
effectively executes in one cycle. If an instruction
causes the program counter to change (e.g., GOTO)
then two cycles are required to complete the instruction
(Example 3-1).
A fetch cycle begins with the Program Counter (PC)
incrementing in Q1.
In the execution cycle, the fetched instruction is latched
into the “Instruction Register” in cycle Q1. This
instruction is then decoded and executed during the
Q2, Q3, and Q4 cycles. Data memory is read during Q2
(operand read) and written during Q4 (destination
write).
FIGURE 3-2:
CLOCK/INSTRUCTION CYCLE
Q1
Q2
Q3
Q4
Q1
Q2
Q3
Q4
Q1
Q2
Q3
Q4
OSC1
Q1
Q2
Internal
phase
clock
Q3
Q4
PC
PC
OSC2/CLKOUT
(RC mode)
EXAMPLE 3-1:
Fetch INST (PC)
Execute INST (PC-1)
PC+2
Fetch INST (PC+1)
Execute INST (PC)
Fetch INST (PC+2)
Execute INST (PC+1)
INSTRUCTION PIPELINE FLOW
1. MOVLW 55h
2. MOVWF PORTB
3. CALL SUB_1
4. BSF
PC+1
PORTA, BIT3
Fetch 1
Execute 1
Fetch 2
Execute 2
Fetch 3
Execute 3
Fetch 4
Flush
Fetch SUB_1 Execute SUB_1
All instructions are single cycle, except for any program branches. These take two cycles since the fetch
instruction is “flushed” from the pipeline while the new instruction is being fetched and then executed.
DS30430B-page 10
PIC16F8X
MEMORY ORGANIZATION
There are two memory blocks in the PIC16F8X. These
are the program memory and the data memory. Each
block has its own bus, so that access to each block can
occur during the same oscillator cycle.
The data memory can further be broken down into the
general purpose RAM and the Special Function
Registers (SFRs). The operation of the SFRs that
control the “core” are described here. The SFRs used
to control the peripheral modules are described in the
section discussing each individual peripheral module.
The data memory area also contains the data
EEPROM memory. This memory is not directly mapped
into the data memory, but is indirectly mapped. That is,
an indirect address pointer specifies the address of the
data EEPROM memory to read/write. The 64 bytes of
data EEPROM memory have the address range
0h-3Fh. More details on the EEPROM memory can be
found in Section 7.0.
4.1
FIGURE 4-1: PROGRAM MEMORY MAP
AND STACK PIC16F83/CR83
PC<12:0>
13
CALL, RETURN
RETFIE, RETLW
Stack Level 1
•
•
•
Stack Level 8
User Memory
Space
4.0
Reset Vector
0000h
Peripheral Interrupt Vector
0004h
1FFh
Program Memory Organization
The PIC16FXX has a 13-bit program counter capable
of addressing an 8K x 14 program memory space. For
the PIC16F83 and PIC16CR83, the first 512 x 14
(0000h-01FFh)
are
physically
implemented
(Figure 4-1). For the PIC16F84 and PIC16CR84, the
first 1K x 14 (0000h-03FFh) are physically implemented (Figure 4-2). Accessing a location above the
physically implemented address will cause a wraparound. For example, for the PIC16F84 locations 20h,
420h, 820h, C20h, 1020h, 1420h, 1820h, and 1C20h
will be the same instruction.
1FFFh
FIGURE 4-2: PROGRAM MEMORY MAP
AND STACK PIC16F84/CR84
PC<12:0>
13
CALL, RETURN
RETFIE, RETLW
Stack Level 1
The reset vector is at 0000h and the interrupt vector is
at 0004h.
•
•
•
Stack Level 8
0000h
Peripheral Interrupt Vector
0004h
User Memory
Space
Reset Vector
3FFh
1FFFh
DS30430B-page 11
PIC16F8X
4.2
Data Memory Organization
4.2.1
GENERAL PURPOSE REGISTER FILE
The data memory is partitioned into two areas. The first
is the Special Function Registers (SFR) area, while the
second is the General Purpose Registers (GPR) area.
The SFRs control the operation of the device.
All devices have some amount of General Purpose
Register (GPR) area. Each GPR is 8 bits wide and is
accessed either directly or indirectly through the FSR
(Section 4.5).
Portions of data memory are banked. This is for both
the SFR area and the GPR area. The GPR area is
banked to allow greater than 116 bytes of general
purpose RAM. The banked areas of the SFR are for the
registers that control the peripheral functions. Banking
requires the use of control bits for bank selection.
These control bits are located in the STATUS Register.
Figure 4-3 and Figure 4-4 show the data memory map
organization.
The GPR addresses in bank 1 are mapped to
addresses in bank 0. As an example, addressing location 0Ch or 08h will access the same GPR.
Instructions MOVWF and MOVF can move values from
the W register to any location in the register file (“F”),
and vice-versa.
The special function registers can be classified into two
sets, core and peripheral. Those associated with the
core functions are described in this section. Those
related to the operation of the peripheral features are
described in the section for that specific feature.
The entire data memory can be accessed either
directly using the absolute address of each register file
or indirectly through the File Select Register (FSR)
(Section 4.5). Indirect addressing uses the present
value of the RP1:RP0 bits for access into the banked
areas of data memory.
4.2.2
SPECIAL FUNCTION REGISTERS
The Special Function Registers (Figure 4-3, Figure 4-4
and Table 4-1) are used by the CPU and Peripheral
functions to control the device operation. These
registers are static RAM.
Data memory is partitioned into two banks which
contain the general purpose registers and the special
function registers. Bank 0 is selected by clearing the
RP0 bit (STATUS<5>). Setting the RP0 bit selects
Bank 1. Each Bank extends up to 7Fh (128 bytes). The
first twelve locations of each Bank are reserved for the
Special Function Registers. The remainder are General Purpose Registers implemented as static RAM.
DS30430B-page 12
PIC16F8X
FIGURE 4-3:
REGISTER FILE MAP PIC16F83/CR83
File Address
FIGURE 4-4:
REGISTER FILE MAP PIC16F84/CR84
File Address
File Address
80h
00h
Indirect addr.(1)
OPTION
81h
01h
TMR0
OPTION
81h
PCL
82h
02h
PCL
PCL
82h
STATUS
STATUS
83h
03h
STATUS
STATUS
83h
FSR
FSR
84h
04h
FSR
FSR
84h
05h
PORTA
TRISA
85h
05h
PORTA
TRISA
85h
06h
PORTB
TRISB
86h
06h
PORTB
TRISB
86h
87h
07h
08h
EEDATA
EECON1
88h
08h
EEDATA
EECON1
88h
09h
EEADR
EECON2(1)
89h
09h
EEADR
EECON2(1)
89h
0Ah
PCLATH
PCLATH
8Ah
0Ah
PCLATH
PCLATH
8Ah
0Bh
INTCON
INTCON
8Bh
0Bh
INTCON
INTCON
8Bh
8Ch
0Ch
00h
Indirect addr.(1)
01h
TMR0
02h
PCL
03h
04h
Indirect addr.(1)
07h
0Ch
36
General
Purpose
registers
(SRAM)
Mapped
(accesses)
in Bank 0
8Ch
Mapped
(accesses)
in Bank 0
4Fh
50h
7Fh
FFh
Bank 0
Bank 1
Unimplemented data memory location; read as '0'.
Note 1: Not a physical register.
80h
87h
68
General
Purpose
registers
(SRAM)
AFh
B0h
2Fh
30h
File Address
Indirect addr.(1)
CFh
D0h
7Fh
FFh
Bank 0
Bank 1
Unimplemented data memory location; read as '0'.
Note 1: Not a physical register.
DS30430B-page 13
PIC16F8X
TABLE 4-1:
Address
REGISTER FILE SUMMARY
Name
Bit 7
Bit 6
Bit 5
Bit 4
Bit 3
Bit 2
Bit 1
Bit 0
Value on
Power-on
Reset
Value on all
other resets
(Note3)
Bank 0
00h
INDF
Uses contents of FSR to address data memory (not a physical register)
---- ----
---- ----
01h
TMR0
8-bit real-time clock/counter
xxxx xxxx
uuuu uuuu
02h
PCL
Low order 8 bits of the Program Counter (PC)
0000 0000
0000 0000
(2)
TO
PD
Z
DC
03h
STATUS
04h
FSR
05h
PORTA
—
—
—
RA4/T0CKI
RA3
RA2
RA1
06h
PORTB
RB7
RB6
RB5
RB4
RB3
RB2
RB1
07h
IRP
RP1
RP0
C
0001 1xxx
000q quuu
xxxx xxxx
uuuu uuuu
RA0
---x xxxx
---u uuuu
RB0/INT
xxxx xxxx
uuuu uuuu
Unimplemented location, read as '0'
---- ----
---- ---uuuu uuuu
Indirect data memory address pointer 0
08h
EEDATA
EEPROM data register
xxxx xxxx
09h
EEADR
EEPROM address register
xxxx xxxx
uuuu uuuu
0Ah
PCLATH
—
—
—
---0 0000
---0 0000
0Bh
INTCON
GIE
EEIE
T0IE
0000 000u
Write buffer for upper 5 bits of the PC (1)
INTE
RBIE
T0IF
INTF
RBIF
0000 000x
---- ----
---- ----
PS1
PS0
1111 1111
1111 1111
0000 0000
0000 0000
0001 1xxx
000q quuu
Bank 1
80h
INDF
81h
OPTION
82h
PCL
83h
STATUS (2)
84h
FSR
85h
TRISA
86h
TRISB
87h
Uses contents of FSR to address data memory (not a physical register)
RBPU
INTEDG
T0CS
T0SE
PSA
PS2
Low order 8 bits of Program Counter (PC)
IRP
RP1
RP0
TO
PD
Z
DC
C
Indirect data memory address pointer 0
—
—
—
PORTA data direction register
xxxx xxxx
uuuu uuuu
---1 1111
---1 1111
PORTB data direction register
1111 1111
1111 1111
Unimplemented location, read as '0'
---- ----
---- ----
---0 x000
---0 q000
88h
EECON1
—
—
—
89h
EECON2
0Ah
PCLATH
—
—
—
0Bh
INTCON
GIE
EEIE
T0IE
EEIF
WRERR
WREN
WR
RD
EEPROM control register 2 (not a physical register)
Write buffer for upper 5 bits of the PC (1)
INTE
RBIE
T0IF
INTF
RBIF
---- ----
---- ----
---0 0000
---0 0000
0000 000x
0000 000u
Legend: x = unknown, u = unchanged. - = unimplemented read as '0', q = value depends on condition.
Note 1: The upper byte of the program counter is not directly accessible. PCLATH is a slave register for PC<12:8>. The contents
of PCLATH can be transferred to the upper byte of the program counter, but the contents of PC<12:8> is never transferred to PCLATH.
2: The TO and PD status bits in the STATUS register are not affected by a MCLR reset.
3: Other (non power-up) resets include: external reset through MCLR and the Watchdog Timer Reset.
DS30430B-page 14
PIC16F8X
4.2.2.1
STATUS REGISTER
The STATUS register contains the arithmetic status of
the ALU, the RESET status and the bank select bit for
data memory.
As with any register, the STATUS register can be the
destination for any instruction. If the STATUS register is
the destination for an instruction that affects the Z, DC
or C bits, then the write to these three bits is disabled.
These bits are set or cleared according to device logic.
Furthermore, the TO and PD bits are not writable.
Therefore, the result of an instruction with the STATUS
register as destination may be different than intended.
For example, CLRF STATUS will clear the upper-three
bits and set the Z bit. This leaves the STATUS register
as 000u u1uu (where u = unchanged).
FIGURE 4-5:
R/W-0
IRP
Only the BCF, BSF, SWAPF and MOVWF instructions
should be used to alter the STATUS register (Table 9-2)
because these instructions do not affect any status bit.
Note 1: The IRP and RP1 bits (STATUS<7:6>) are
not used by the PIC16F8X and should be
programmed as cleared. Use of these bits
as general purpose R/W bits is NOT
recommended, since this may affect
upward compatibility with future products.
Note 2: The C and DC bits operate as a borrow
and digit borrow out bit, respectively, in
subtraction. See the SUBLW and SUBWF
instructions for examples.
Note 3: When the STATUS register is the
destination for an instruction that affects
the Z, DC or C bits, then the write to these
three bits is disabled. The specified bit(s)
will be updated according to device logic
STATUS REGISTER (ADDRESS 03h, 83h)
R/W-0
RP1
R/W-0
RP0
R-1
TO
R-1
PD
R/W-x
Z
R/W-x
DC
bit7
bit 7:
R/W-x
C
bit0
R = Readable bit
W = Writable bit
U = Unimplemented bit,
read as ‘0’
- n = Value at POR reset
IRP: Register Bank Select bit (used for indirect addressing)
0 = Bank 0, 1 (00h - FFh)
1 = Bank 2, 3 (100h - 1FFh)
The IRP bit is not used by the PIC16F8X. IRP should be maintained clear.
bit 6-5: RP1:RP0: Register Bank Select bits (used for direct addressing)
00 = Bank 0 (00h - 7Fh)
01 = Bank 1 (80h - FFh)
10 = Bank 2 (100h - 17Fh)
11 = Bank 3 (180h - 1FFh)
Each bank is 128 bytes. Only bit RP0 is used by the PIC16F8X. RP1 should be maintained clear.
bit 4:
TO: Time-out bit
1 = After power-up, CLRWDT instruction, or SLEEP instruction
0 = A WDT time-out occurred
bit 3:
PD: Power-down bit
1 = After power-up or by the CLRWDT instruction
0 = By execution of the SLEEP instruction
bit 2:
Z: Zero bit
1 = The result of an arithmetic or logic operation is zero
0 = The result of an arithmetic or logic operation is not zero
bit 1:
DC: Digit carry/borrow bit (for ADDWF and ADDLW instructions) (For borrow the polarity is reversed)
1 = A carry-out from the 4th low order bit of the result occurred
0 = No carry-out from the 4th low order bit of the result
bit 0:
C: Carry/borrow bit (for ADDWF and ADDLW instructions)
1 = A carry-out from the most significant bit of the result occurred
0 = No carry-out from the most significant bit of the result occurred
Note:For borrow the polarity is reversed. A subtraction is executed by adding the two’s complement of
the second operand. For rotate (RRF, RLF) instructions, this bit is loaded with either the high or low
order bit of the source register.
DS30430B-page 15
PIC16F8X
4.2.2.2
OPTION REGISTER
Note:
The OPTION register is a readable and writable
register which contains various control bits to configure
the TMR0/WDT prescaler, the external INT interrupt,
TMR0, and the weak pull-ups on PORTB.
FIGURE 4-6:
R/W-1
RBPU
bit7
When the prescaler is assigned to
the WDT (PSA = '1'), TMR0 has a 1:1
prescaler assignment.
OPTION REGISTER (ADDRESS 81h)
R/W-1
INTEDG
R/W-1
T0CS
R/W-1
T0SE
R/W-1
PSA
R/W-1
PS2
R/W-1
PS1
R/W-1
PS0
bit0
bit 7:
RBPU: PORTB Pull-up Enable bit
1 = PORTB pull-ups are disabled
0 = PORTB pull-ups are enabled (by individual port latch values)
bit 6:
INTEDG: Interrupt Edge Select bit
1 = Interrupt on rising edge of RB0/INT pin
0 = Interrupt on falling edge of RB0/INT pin
bit 5:
T0CS: TMR0 Clock Source Select bit
1 = Transition on RA4/T0CKI pin
0 = Internal instruction cycle clock (CLKOUT)
bit 4:
T0SE: TMR0 Source Edge Select bit
1 = Increment on high-to-low transition on RA4/T0CKI pin
0 = Increment on low-to-high transition on RA4/T0CKI pin
bit 3:
PSA: Prescaler Assignment bit
1 = Prescaler assigned to the WDT
0 = Prescaler assigned to TMR0
R = Readable bit
W = Writable bit
read as ‘0’
bit 2-0: PS2:PS0: Prescaler Rate Select bits
Bit Value
000
001
010
011
100
101
110
111
DS30430B-page 16
TMR0 Rate
1:2
1:4
1:8
1 : 16
1 : 32
1 : 64
1 : 128
1 : 256
WDT Rate
1:1
1:2
1:4
1:8
1 : 16
1 : 32
1 : 64
1 : 128
PIC16F8X
4.2.2.3
INTCON REGISTER
Note:
The INTCON register is a readable and writable
register which contains the various enable bits for all
interrupt sources.
FIGURE 4-7:
R/W-0
GIE
bit7
bit 7:
Interrupt flag bits get set when an interrupt
condition occurs regardless of the state of
its corresponding enable bit or the global
enable bit, GIE (INTCON<7>).
INTCON REGISTER (ADDRESS 0Bh, 8Bh)
R/W-0
EEIE
R/W-0
T0IE
R/W-0
INTE
R/W-0
RBIE
R/W-0
T0IF
R/W-0
INTF
R/W-x
RBIF
bit0
R = Readable bit
W = Writable bit
read as ‘0’
GIE: Global Interrupt Enable bit
1 = Enables all un-masked interrupts
0 = Disables all interrupts
Note: For the operation of the interrupt structure, please refer to Section 8.5.
bit 6:
EEIE: EE Write Complete Interrupt Enable bit
1 = Enables the EE write complete interrupt
0 = Disables the EE write complete interrupt
bit 5:
T0IE: TMR0 Overflow Interrupt Enable bit
1 = Enables the TMR0 interrupt
0 = Disables the TMR0 interrupt
bit 4:
INTE: RB0/INT Interrupt Enable bit
1 = Enables the RB0/INT interrupt
0 = Disables the RB0/INT interrupt
bit 3:
RBIE: RB Port Change Interrupt Enable bit
1 = Enables the RB port change interrupt
0 = Disables the RB port change interrupt
bit 2:
T0IF: TMR0 overflow interrupt flag bit
1 = TMR0 has overflowed (must be cleared in software)
0 = TMR0 did not overflow
bit 1:
INTF: RB0/INT Interrupt Flag bit
1 = The RB0/INT interrupt occurred
0 = The RB0/INT interrupt did not occur
bit 0:
RBIF: RB Port Change Interrupt Flag bit
1 = When at least one of the RB7:RB4 pins changed state (must be cleared in software)
0 = None of the RB7:RB4 pins have changed state
DS30430B-page 17
PIC16F8X
4.3
Program Counter: PCL and PCLATH
The Program Counter (PC) is 13-bits wide. The low
byte is the PCL register, which is a readable and
writable register. The high byte of the PC (PC<12:8>) is
not directly readable nor writable and comes from the
PCLATH register. The PCLATH (PC latch high) register
is a holding register for PC<12:8>. The contents of
PCLATH are transferred to the upper byte of the
program counter when the PC is loaded with a new
value. This occurs during a CALL, GOTO or a write to
PCL. The high bits of PC are loaded from PCLATH as
shown in Figure 4-8.
FIGURE 4-8:
LOADING OF PC IN
DIFFERENT SITUATIONS
PCH
PCL
12
8 7
0
INST with PCL
as dest
PC
8
PCLATH<4:0>
5
ALU result
PCLATH
PCH
12 11 10
4.4
8 7
PCLATH<4:3>
11
Opcode <10:0>
COMPUTED GOTO
A computed GOTO is accomplished by adding an offset
to the program counter (ADDWF PCL). When doing a
table read using a computed GOTO method, care
should be exercised if the table location crosses a PCL
memory boundary (each 256 word block). Refer to the
application note “Implementing a Table Read” (AN556).
Stack
The entire 13-bit PC is “pushed” onto the stack when a
CALL instruction is executed or an interrupt is acknowledged. The stack is “popped” in the event of a
RETURN, RETLW or a RETFIE instruction execution.
PCLATH is not affected by a push or a pop operation.
0
PCLATH
The PIC16F8X ignores the PCLATH<4:3>
bits, which are used for program memory
pages 1, 2 and 3 (0800h - 1FFFh). The
use of PCLATH<4:3> as general purpose
R/W bits is not recommended since this
may affect upward compatibility with
future products.
The PIC16FXX has an 8 deep x 13-bit wide hardware
stack (Figure 4-1). The stack space is not part of either
program or data space and the stack pointer is not
readable or writable.
GOTO, CALL
2
4.3.2
Note:
Note:
PCL
PC
4.3.1
manipulation of the PCLATH<4:3> is not required for
the return instructions (which “pops” the PC from the
stack).
There are no instruction mnemonics
called push or pop. These are actions that
occur from the execution of the CALL,
RETURN, RETLW, and RETFIE instructions, or the vectoring to an interrupt
address.
The stack operates as a circular buffer. That is, after the
stack has been pushed eight times, the ninth push overwrites the value that was stored from the first push. The
tenth push overwrites the second push (and so on).
If the stack is effectively popped nine times, the PC
value is the same as the value from the first pop.
Note:
There are no status bits to indicate stack
overflow or stack underflow conditions.
PROGRAM MEMORY PAGING
The PIC16F83 and PIC16CR83 have 512 words of program memory. The PIC16F84 and PIC16CR84 have
1K of program memory. The CALL and GOTO instructions have an 11-bit address range. This 11-bit address
range allows a branch within a 2K program memory
page size. For future PIC16F8X program memory
expansion, there must be another two bits to specify
the program memory page. These paging bits come
from the PCLATH<4:3> bits (Figure 4-8). When doing a
CALL or a GOTO instruction, the user must ensure that
these page bits (PCLATH<4:3>) are programmed to
the desired program memory page. If a CALL instruction (or interrupt) is executed, the entire 13-bit PC is
“pushed” onto the stack (see next section). Therefore,
DS30430B-page 18
PIC16F8X
4.5
Indirect Addressing; INDF and FSR
Registers
EXAMPLE 4-2:
The INDF register is not a physical register. Addressing INDF actually addresses the register whose
address is contained in the FSR register (FSR is a
pointer). This is indirect addressing.
EXAMPLE 4-1:
movlw
movwf
clrf
incf
btfss
goto
NEXT
INDIRECT ADDRESSING
•
•
•
•
Register file 05 contains the value 10h
Register file 06 contains the value 0Ah
Load the value 05 into the FSR register
A read of the INDF register will return the value of
10h
• Increment the value of the FSR register by one
(FSR = 06)
• A read of the INDR register now will return the
value of 0Ah.
HOW TO CLEAR RAM
USING INDIRECT
ADDRESSING
0x20
FSR
INDF
FSR
FSR,4
NEXT
;initialize pointer
; to RAM
;clear INDF register
;inc pointer
;all done?
;NO, clear next
CONTINUE
:
;YES, continue
An effective 9-bit address is obtained by concatenating
the 8-bit FSR register and the IRP bit (STATUS<7>), as
shown in Figure 4-9. However, IRP is not used in the
PIC16F8X.
Reading INDF itself indirectly (FSR = 0) will produce
00h. Writing to the INDF register indirectly results in a
no-operation (although STATUS bits may be affected).
A simple program to clear RAM locations 20h-2Fh
using indirect addressing is shown in Example 4-2.
FIGURE 4-9:
DIRECT/INDIRECT ADDRESSING
Indirect Addressing
Direct Addressing
RP1 RP0
bank select
6
from opcode
0
IRP
location select
7
bank select
00
01
10
11
not used
not used
Bank 2
Bank 3
(FSR)
0
location select
00h
00h
0Bh
0Ch
Data
Memory (3)
Addresses
map back
to Bank 0
2Fh (1)
30h (1)
4Fh (2)
50h (2)
7Fh
7Fh
Bank 0
Bank 1
Note 1: PIC16F83 and PIC16CR83 devices.
2: PIC16F84 and PIC16CR84 devices
3: For memory map detail see Figure 4-1.
DS30430B-page 19
PIC16F8X
NOTES:
DS30430B-page 20
PIC16F8X
5.0
I/O PORTS
EXAMPLE 5-1:
The PIC16F8X has two ports, PORTA and PORTB.
Some port pins are multiplexed with an alternate function for other features on the device.
5.1
PORTA and TRISA Registers
PORTA is a 5-bit wide latch. RA4 is a Schmitt Trigger
input and an open drain output. All other RA port pins
have TTL input levels and full CMOS output drivers. All
pins have data direction bits (TRIS registers) which can
configure these pins as output or input.
Setting a TRISA bit (=1) will make the corresponding
PORTA pin an input, i.e., put the corresponding output
driver in a hi-impedence mode. Clearing a TRISA bit
(=0) will make the corresponding PORTA pin an output,
i.e., put the contents of the output latch on the selected
pin.
Reading the PORTA register reads the status of the pins
whereas writing to it will write to the port latch. All write
operations are read-modify-write operations. So a write
to a port implies that the port pins are first read, then this
value is modified and written to the port data latch.
The RA4 pin is multiplexed with the TMR0 clock input.
FIGURE 5-1:
Data
bus
WR
Port
INITIALIZING PORTA
CLRF
PORTA
BSF
MOVLW
STATUS, RP0
0x0F
MOVWF
TRISA
FIGURE 5-2:
;
;
;
;
;
;
;
;
;
;
;
Initialize PORTA by
setting output
data latches
Select Bank 1
Value used to
initialize data
direction
Set RA<3:0> as inputs
RA4 as outputs
TRISA<7:5> are always
read as '0'.
BLOCK DIAGRAM OF PIN RA4
Data
bus
WR
PORT
D
Q
CK
Q
N
RA4 pin
Data Latch
VSS
WR
TRIS
D
Q
CK
Q
Schmitt
Trigger
input
buffer
TRIS Latch
BLOCK DIAGRAM OF PINS
RA3:RA0
RD TRIS
D
Q
Q
VDD
CK
Q
D
EN
EN
P
RD PORT
Data Latch
N
D
WR
TRIS
I/O pin
Q
VSS
CK
TMR0 clock input
Note: I/O pin has protection diodes to VSS only.
Q
TRIS Latch
TTL
input
buffer
RD TRIS
Q
D
EN
RD PORT
Note: I/O pins have protection diodes to VDD and VSS.
DS30430B-page 21
PIC16F8X
TABLE 5-1:
PORTA FUNCTIONS
Name
Bit0
Buffer Type
RA0
RA1
RA2
RA3
RA4/T0CKI
bit0
bit1
bit2
bit3
bit4
TTL
TTL
TTL
TTL
ST
Function
Input/output
Input/output
Input/output
Input/output
Input/output or external clock input for TMR0.
Output is open drain type.
Legend: TTL = TTL input, ST = Schmitt Trigger input
TABLE 5-2:
Address
Name
05h
85h
SUMMARY OF REGISTERS ASSOCIATED WITH PORTA
Bit 7
Bit 6
Bit 5
Bit 4
Bit 3
Bit 2
PORTA
—
—
—
RA4/T0CKI
RA3
RA2
TRISA
—
—
—
TRISA4
TRISA3
TRISA2
Bit 0
Value on
Power-on
Reset
Value on all
other resets
RA1
RA0
---x xxxx
---u uuuu
TRISA1
TRISA0
---1 1111
---1 1111
Bit 1
Legend: x = unknown, u = unchanged, - = unimplemented read as '0'. Shaded cells are unimplemented, read as '0'
DS30430B-page 22
PIC16F8X
PORTB and TRISB Registers
5.2
PORTB is an 8-bit wide bi-directional port. The
corresponding data direction register is TRISB. A '1' on
any bit in the TRISB register puts the corresponding
output driver in a hi-impedance mode. A '0' on any bit
in the TRISB register puts the contents of the output
latch on the selected pin(s).
Each of the PORTB pins have a weak internal pull-up.
A single control bit can turn on all the pull-ups. This is
done by clearing the RBPU (OPTION<7>) bit. The
weak pull-up is automatically turned off when the port
pin is configured as an output. The pull-ups are
disabled on a Power-on Reset.
Four of PORTB’s pins, RB7:RB4, have an interrupt on
change feature. Only pins configured as inputs can
cause this interrupt to occur (i.e., any RB7:RB4 pin
configured as an output is excluded from the interrupt
on change comparison). The pins value in input mode
are compared with the old value latched on the last
read of PORTB. The “mismatch” outputs of the pins are
OR’ed together to generate the RB port
change interrupt.
FIGURE 5-3:
RB7:RB4
This interrupt can wake the device from SLEEP. The
user, in the interrupt service routine, can clear the
interrupt in the following manner:
a)
b)
Read (or write) PORTB. This will end the mismatch condition.
Clear flag bit RBIF.
A mismatch condition will continue to set the RBIF bit.
Reading PORTB will end the mismatch condition, and
allow the RBIF bit to be cleared.
This interrupt on mismatch feature, together with
software configurable pull-ups on these four pins allow
easy interface to a key pad and make it possible for
wake-up on key-depression (see AN552 in the
Embedded Control Handbook).
Note 1: For a change on the I/O pin to be
recognized, the pulse width must be at
least TCY wide.
The interrupt on change feature is recommended for
wake-up on key depression operation and operations
where PORTB is only used for the interrupt on change
feature. Polling of PORTB is not recommended while
using the interrupt on change feature.
FIGURE 5-4:
RB3:RB0
VDD
RBPU(1)
VDD
RBPU(1)
Data bus
weak
P pull-up
Data Latch
D
WR Port
Q
I/O
pin(2)
CK
Data bus
WR Port
WR TRIS
WR TRIS
Q
Data Latch
D
Q
I/O
pin(2)
CK
TRIS Latch
D
Q
TRIS Latch
D
weak
P pull-up
TTL
Input
Buffer
CK
TTL
Input
Buffer
CK
RD TRIS
Q
Latch
RD TRIS
Q
RD Port
D
RD Port
D
EN
EN
Set RBIF
RB0/INT
From other
RB7:RB4 pins
Q
Schmitt Trigger
Buffer
D
RD Port
Note 1: TRISB = '1' enables weak pull-up
(if RBPU = '0' in the OPTION register).
EN
2: I/O pins have diode protection to VDD and VSS.
RD Port
Note 1: TRISB = '1' enables weak pull-up
(if RBPU = '0' in the OPTION register).
2: I/O pins have diode protection to VDD and VSS.
DS30430B-page 23
PIC16F8X
EXAMPLE 5-2:
INITIALIZING PORTB
CLRF
PORTB
BSF
MOVLW
STATUS, RP0
0xCF
MOVWF
TRISB
TABLE 5-3:
Initialize PORTB by
setting output
data latches
Select Bank 1
Value used to
initialize data
direction
Set RB<3:0> as inputs
RB<5:4> as outputs
RB<7:6> as inputs
PORTB FUNCTIONS
Name
RB0/INT
;
;
;
;
;
;
;
;
;
;
Bit
Buffer Type
I/O Consistency Function
(1)
bit0
Input/output pin or external interrupt input. Internal software
programmable weak pull-up.
RB1
bit1
TTL
Input/output pin. Internal software programmable weak pull-up.
RB2
bit2
TTL
RB3
bit3
TTL
RB4
bit4
TTL
Input/output pin (with interrupt on change). Internal software programmable
weak pull-up.
RB5
bit5
TTL
weak pull-up.
RB6
bit6
TTL/ST(2)
weak pull-up. Serial programming clock.
RB7
bit7
TTL/ST(2)
weak pull-up. Serial programming data.
Legend: TTL = TTL input, ST = Schmitt Trigger.
Note 1: This buffer is a Schmitt Trigger input when configured as the external interrupt.
2: This buffer is a Schmitt Trigger input when used in serial programming mode.
TABLE 5-4:
Address
Name
TTL/ST
SUMMARY OF REGISTERS ASSOCIATED WITH PORTB
Bit 7
Bit 6
Bit 5
Bit 4
Bit 3
Bit 2
Bit 1
Bit 0
Value on
Power-on
Reset
Value on all
other resets
uuuu uuuu
06h
PORTB
RB7
RB6
RB5
RB4
RB3
RB2
RB1
RB0/INT
xxxx xxxx
86h
TRISB
TRISB7
TRISB6
TRISB5
TRISB4
TRISB3
TRISB2
TRISB1
TRISB0
1111 1111
1111 1111
81h
OPTION
RBPU
INTEDG
T0CS
T0SE
PSA
PS2
PS1
PS0
1111 1111
1111 1111
Legend: x = unknown, u = unchanged. Shaded cells are not used by PORTB.
DS30430B-page 24
PIC16F8X
5.3
I/O Programming Considerations
5.3.2
5.3.1
BI-DIRECTIONAL I/O PORTS
The actual write to an I/O port happens at the end of an
instruction cycle, whereas for reading, the data must be
valid at the beginning of the instruction cycle
(Figure 5-5). Therefore, care must be exercised if a
write followed by a read operation is carried out on the
same I/O port. The sequence of instructions should be
such that the pin voltage stabilizes (load dependent)
before the next instruction which causes that file to be
read into the CPU is executed. Otherwise, the previous
state of that pin may be read into the CPU rather than
the new state. When in doubt, it is better to separate
these instructions with a NOP or another instruction not
accessing this I/O port.
Any instruction which writes, operates internally as a
read followed by a write operation. The BCF and BSF
instructions, for example, read the register into the
CPU, execute the bit operation and write the result
back to the register. Caution must be used when these
instructions are applied to a port with both inputs and
outputs defined. For example, a BSF operation on bit5
of PORTB will cause all eight bits of PORTB to be read
into the CPU. Then the BSF operation takes place on
bit5 and PORTB is written to the output latches. If
another bit of PORTB is used as a bi-directional I/O pin
(i.e., bit0) and it is defined as an input at this time, the
input signal present on the pin itself would be read into
the CPU and rewritten to the data latch of this particular
pin, overwriting the previous content. As long as the pin
stays in the input mode, no problem occurs. However,
if bit0 is switched into output mode later on, the content
of the data latch is unknown.
Reading the port register, reads the values of the port
pins. Writing to the port register writes the value to the
port latch. When using read-modify-write instructions
(i.e., BCF, BSF, etc.) on a port, the value of the port pins
is read, the desired operation is done to this value, and
this value is then written to the port latch.
A pin actively outputting a Low or High should not be
driven from external devices at the same time in order
to change the level on this pin (“wired-or”, “wired-and”).
The resulting high output current may damage the chip.
FIGURE 5-5:
SUCCESSIVE OPERATIONS ON I/O PORTS
Example 5-3 shows the effect of two sequential
read-modify-write instructions (e.g., BCF, BSF, etc.) on
an I/O port.
EXAMPLE 5-3:
;Initial PORT settings: PORTB<7:4> Inputs
;
PORTB<3:0> Outputs
;PORTB<7:6> have external pull-ups and are
;not connected to other circuitry
;
;
PORT latch PORT pins
;
---------- --------BCF PORTB, 7
; 01pp ppp
11pp ppp
BCF PORTB, 6
; 10pp ppp
11pp ppp
BSF STATUS, RP0 ;
BCF TRISB, 7
; 10pp ppp
11pp ppp
BCF TRISB, 6
; 10pp ppp
10pp ppp
;
;Note that the user may have expected the
;pin values to be 00pp ppp. The 2nd BCF
;caused RB7 to be latched as the pin value
;(high).
SUCCESSIVE I/O OPERATION
Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4
PC
Instruction
fetched
MOVWF PORTB
write to
PORTB
PC + 1
PC + 2
PC + 3
NOP
NOP
MOVF PORTB,W
Port pin
sampled here
MOVWF PORTB
write to
PORTB
This example shows as write to PORTB
followed by a read from PORTB.
Therefore, at higher clock frequencies, a write
followed by a read may be problematic.
MOVF PORTB,W
NOP
Note:
Note that:
data setup time = (0.25 TCY - TPD)
where:TCY = instruction cycle
TPD = propagation delay
RB7:RB0
Instruction
executed
READ-MODIFY-WRITE
INSTRUCTIONS ON AN
I/O PORT
NOP
DS30430B-page 25
PIC16F8X
NOTES:
DS30430B-page 26
PIC16F8X
6.0
TIMER0 MODULE AND TMR0
REGISTER
edge select bit, T0SE (OPTION<4>). Clearing bit T0SE
selects the rising edge. Restrictions on the external
clock input are discussed in detail in Section 6.2.
The Timer0 module timer/counter has the following
features:
•
•
•
•
•
•
The prescaler is shared between the Timer0 Module
and the Watchdog Timer. The prescaler assignment is
controlled, in software, by control bit PSA
(OPTION<3>). Clearing bit PSA will assign the
prescaler to the Timer0 Module. The prescaler is not
readable or writable. When the prescaler (Section 6.3)
is assigned to the Timer0 Module, the prescale value
(1:2, 1:4, ..., 1:256) is software selectable.
8-bit timer/counter
Readable and writable
8-bit software programmable prescaler
Internal or external clock select
Interrupt on overflow from FFh to 00h
Edge select for external clock
The TMR0 interrupt is generated when the TMR0
register overflows from FFh to 00h. This overflow sets
the T0IF bit (INTCON<2>). The interrupt can be
masked by clearing enable bit T0IE (INTCON<5>). The
T0IF bit must be cleared in software by the Timer0
Module interrupt service routine before re-enabling this
interrupt. The TMR0 interrupt (Figure 6-4) cannot wake
the processor from SLEEP since the timer is shut off
during SLEEP.
Counter mode is selected by setting the T0CS bit
(OPTION<5>). In this mode TMR0 will increment either
on every rising or falling edge of pin RA4/T0CKI. The
incrementing edge is determined by the T0 source
FIGURE 6-1:
TMR0 Interrupt
6.1
Timer mode is selected by clearing the T0CS bit
(OPTION<5>). In timer mode, the Timer0 module
(Figure 6-1) will increment every instruction cycle
(without prescaler). If the TMR0 register is written, the
increment is inhibited for the following two cycles
(Figure 6-2 and Figure 6-3). The user can work around
this by writing an adjusted value to the TMR0 register.
TMR0 BLOCK DIAGRAM
Data bus
FOSC/4
0
PSout
1
Sync with
Internal
clocks
1
RA4/T0CKI
pin
Programmable
Prescaler
8
0
TMR0 register
PSout
(2 cycle delay)
T0SE
3
PS2, PS1, PS0
Set bit T0IF
on Overflow
PSA
T0CS
Note 1: Bits T0CS, T0SE, PS2, PS1, PS0 and PSA are located in the OPTION register.
2: The prescaler is shared with the Watchdog Timer (Figure 6-6)
FIGURE 6-2:
TMR0 TIMING: INTERNAL CLOCK/NO PRESCALER
Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4
PC-1
PC
MOVWF TMR0
Instruction
Fetch
TMR0
PC
T0
T0+1
Instruction
Executed
PC+1
PC+2
PC+3
MOVF TMR0,W MOVF TMR0,W MOVF TMR0,W
T0+2
NT0
NT0
Write TMR0
executed
Read TMR0
reads NT0
Read TMR0
reads NT0
PC+4
MOVF TMR0,W
NT0
Read TMR0
reads NT0
PC+5
PC+6
MOVF TMR0,W
NT0+1
Read TMR0
reads NT0 + 1
NT0+2
T0
Read TMR0
reads NT0 + 2
DS30430B-page 27
PIC16F8X
FIGURE 6-3:
TMR0 TIMING: INTERNAL CLOCK/PRESCALE 1:2
Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4
PC-1
PC
PC
PC+1
MOVWF TMR0
Instruction
Fetch
PC+3
T0+1
T0
TMR0
PC+2
Instruction
Execute
PC+5
MOVF TMR0,W
PC+6
MOVF TMR0,W
NT0+1
NT0
Write TMR0
executed
FIGURE 6-4:
PC+4
MOVF TMR0,W MOVF TMR0,W MOVF TMR0,W
Read TMR0
reads NT0
Read TMR0
reads NT0
Read TMR0
reads NT0
Read TMR0
reads NT0
Read TMR0
reads NT0 + 1
TMR0 INTERRUPT TIMING
Q1
Q2
Q3
Q4
Q1
Q2
Q3
Q4
Q1
Q2
Q3
Q4
Q1
Q2
Q3
Q4
Q1
Q2
Q3
Q4
OSC1
CLKOUT(3)
TMR0 timer
FEh
T0IF bit 4
(INTCON<2>)
1
FFh
00h
01h
02h
1
GIE bit
(INTCON<7>)
Interrupt Latency(2)
INSTRUCTION FLOW
PC
PC
Instruction
fetched
Inst (PC)
Instruction
executed
Inst (PC-1)
PC +1
PC +1
Inst (PC+1)
Inst (PC)
Dummy cycle
0004h
0005h
Inst (0004h)
Inst (0005h)
Dummy cycle
Inst (0004h)
Note 1: T0IF interrupt flag is sampled here (every Q1).
2: Interrupt latency = 3.25Tcy, where Tcy = instruction cycle time.
3: CLKOUT is available only in RC oscillator mode.
4: The timer clock (after the synchronizer circuit) which increments the timer from FFh to 00h immediately sets the T0IF bit.
The TMR0 register will roll over 3 Tosc cycles later.
DS30430B-page 28
PIC16F8X
6.2
Using TMR0 with External Clock
6.2.2
TMR0 INCREMENT DELAY
When an external clock input is used for TMR0, it must
meet certain requirements. The external clock
requirement is due to internal phase clock (TOSC)
synchronization. Also, there is a delay in the actual
incrementing
of
the
TMR0
register
after
synchronization.
Since the prescaler output is synchronized with the
internal clocks, there is a small delay from the time the
external clock edge occurs to the time the Timer0
Module is actually incremented. Figure 6-5 shows the
delay from the external clock edge to the timer
incrementing.
6.2.1
6.3
EXTERNAL CLOCK SYNCHRONIZATION
Prescaler
When no prescaler is used, the external clock input is
the same as the prescaler output. The synchronization
of pin RA4/T0CKI with the internal phase clocks is
accomplished by sampling the prescaler output on the
Q2 and Q4 cycles of the internal phase clocks
(Figure 6-5). Therefore, it is necessary for T0CKI to be
high for at least 2Tosc (plus a small RC delay) and low
for at least 2Tosc (plus a small RC delay). Refer to the
electrical specification of the desired device.
An 8-bit counter is available as a prescaler for the
Timer0 Module, or as a postscaler for the Watchdog
Timer (Figure 6-6). For simplicity, this counter is being
referred to as “prescaler” throughout this data sheet.
Note that there is only one prescaler available which is
mutually exclusive between the Timer0 Module and the
Watchdog Timer. Thus, a prescaler assignment for the
Timer0 Module means that there is no prescaler for the
Watchdog Timer, and vice-versa.
When a prescaler is used, the external clock input is
divided by an asynchronous ripple counter type
prescaler so that the prescaler output is symmetrical.
For the external clock to meet the sampling
requirement, the ripple counter must be taken into
account. Therefore, it is necessary for T0CKI to have a
period of at least 4Tosc (plus a small RC delay) divided
by the prescaler value. The only requirement on T0CKI
high and low time is that they do not violate the
minimum pulse width requirement of 10 ns. Refer to
parameters 40, 41 and 42 in the AC Electrical
Specifications of the desired device.
The PSA and PS2:PS0 bits (OPTION<3:0>) determine
the prescaler assignment and prescale ratio.
FIGURE 6-5:
When assigned to the Timer0 Module, all instructions
writing to the Timer0 Module (e.g., CLRF 1, MOVWF 1,
BSF 1,x ....etc.) will clear the prescaler. When
assigned to WDT, a CLRWDT instruction will clear the
prescaler along with the Watchdog Timer. The
prescaler is not readable or writable.
TIMER0 TIMING WITH EXTERNAL CLOCK
Q1 Q2 Q3 Q4
Q1 Q2 Q3 Q4
Q1 Q2 Q3 Q4
Q1 Q2 Q3 Q4
Ext. Clock Input or
Prescaler Out (Note 2)
(Note 3)
Ext. Clock/Prescaler
Output After Sampling
Increment TMR0 (Q4)
TMR0
T0
T0 + 1
T0 + 2
Note 1: Delay from clock input change to TMR0 increment is 3Tosc to 7Tosc. (Duration of Q = Tosc).
Therefore, the error in measuring the interval between two edges on TMR0 input = ± 4Tosc max.
2: External clock if no prescaler selected, Prescaler output otherwise.
3: The arrows ↑ indicate where sampling occurs. A small clock pulse may be missed by sampling.
DS30430B-page 29
PIC16F8X
FIGURE 6-6:
BLOCK DIAGRAM OF THE TMR0/WDT PRESCALER
Data Bus
CLKOUT (= Fosc/4)
0
RA4/T0CKI
pin
M
U
X
8
1
M
U
X
0
1
SYNC
2
Cycles
TMR0 register
T0SE
T0CS
0
Watchdog
Timer
1
M
U
X
Set bit T0IF
on overflow
PSA
8-bit Prescaler
8
8 - to - 1MUX
PS2:PS0
PSA
WDT Enable bit
1
0
MUX
PSA
WDT
time-out
Note: T0CS, T0SE, PSA, PS2:PS0 are bits in the OPTION register.
DS30430B-page 30
PIC16F8X
6.3.1
SWITCHING PRESCALER ASSIGNMENT
EXAMPLE 6-1:
The prescaler assignment is fully under software
control (i.e., it can be changed “on the fly” during
program execution).
Note:
To avoid an unintended device RESET,
the following instruction sequence
(Example 6-1) must be executed when
changing the prescaler assignment from
Timer0 to the WDT. This sequence must
be taken even if the WDT is disabled. To
change prescaler from the WDT to the
Timer0 module use the sequence shown
in Example 6-2.
TABLE 6-1:
Address
Name
CHANGING PRESCALER
(TIMER0→WDT)
BCF
CLRF
STATUS, RP0
TMR0
BSF
CLRWDT
MOVLW
MOVWF
BCF
STATUS, RP0
b'xxxx1xxx'
OPTION
STATUS, RP0
EXAMPLE 6-2:
;Bank 0
;Clear TMR0
; and Prescaler
;Bank 1
;Clears WDT
;Select new
; prescale value
;Bank 0
CHANGING PRESCALER
(WDT→TIMER0)
CLRWDT
BSF
MOVLW
STATUS, RP0
b'xxxx0xxx'
MOVWF
BCF
OPTION
STATUS, RP0
;Clear WDT and
; prescaler
;Bank 1
;Select TMR0, new
; prescale value
’ and clock source
;
;Bank 0
REGISTERS ASSOCIATED WITH TIMER0
Bit 7
Bit 6
Bit 5
Bit 4
Bit 3
Bit 2
Bit 1
Bit 0
Value on all
other resets
01h
TMR0
xxxx xxxx
uuuu uuuu
0Bh
INTCON
GIE
EEIE
T0IE
INTE
RBIE
T0IF
INTF
RBIF
0000 000x
0000 0000
81h
OPTION
RBPU
INTEDG
T0CS
T0SE
PSA
PS2
PS1
PS0
1111 1111
1111 1111
—
—
—
TRISA0
---1 1111
---1 1111
85h
TRISA
Timer0 module’s register
Value on
Power-on
Reset
TRISA4
TRISA3
TRISA2
TRISA1
Legend: x = unknown, u = unchanged. - = unimplemented read as '0'. Shaded cells are not associated with Timer0.
DS30430B-page 31
PIC16F8X
NOTES:
DS30430B-page 32
PIC16F8X
7.0
DATA EEPROM MEMORY
The EEPROM data memory is readable and writable
during normal operation (full VDD range). This memory
is not directly mapped in the register file space. Instead
it is indirectly addressed through the Special Function
Registers. There are four SFRs used to read and write
this memory. These registers are:
•
•
•
•
EECON1
EECON2
EEDATA
EEADR
EEDATA holds the 8-bit data for read/write, and
EEADR holds the address of the EEPROM location
being accessed. PIC16F8X devices have 64 bytes of
data EEPROM with an address range from 0h to 3Fh.
When the device is code protected, the CPU may
continue to read and write the data EEPROM memory.
The device programmer can no longer access
this memory.
7.1
EEADR
The EEADR register can address up to a maximum of
256 bytes of data EEPROM. Only the first 64 bytes of
data EEPROM are implemented.
The upper two bits are address decoded. This means
that these two bits must always be '0' to ensure that the
address is in the 64 byte memory space.
The EEPROM data memory allows byte read and write.
A byte write automatically erases the location and
writes the new data (erase before write). The EEPROM
data memory is rated for high erase/write cycles. The
write time is controlled by an on-chip timer. The
write-time will vary with voltage and temperature as
well as from chip to chip. Please refer to AC
specifications for exact limits.
FIGURE 7-1:
EECON1 REGISTER (ADDRESS 88h)
U
U
U
R/W-0
R/W-x
R/W-0
R/S-0
R/S-x
—
—
—
EEIF
WRERR
WREN
WR
RD
bit7
bit0
R
W
S
U
= Readable bit
= Writable bit
= Settable bit
= Unimplemented bit,
read as ‘0’
bit 7:5
Unimplemented: Read as '0'
bit 4
EEIF: EEPROM Write Operation Interrupt Flag bit
1 = The write operation completed (must be cleared in software)
0 = The write operation is not complete or has not been started
bit 3
WRERR: EEPROM Error Flag bit
1 = A write operation is prematurely terminated
(any MCLR reset or any WDT reset during normal operation)
0 = The write operation completed
bit 2
WREN: EEPROM Write Enable bit
1 = Allows write cycles
0 = Inhibits write to the data EEPROM
bit 1
WR: Write Control bit
1 = initiates a write cycle. (The bit is cleared by hardware once write is complete. The WR bit can only be
set (not cleared) in software.
0 = Write cycle to the data EEPROM is complete
bit 0
RD: Read Control bit
1 = Initiates an EEPROM read (read takes one cycle. RD is cleared in hardware. The RD bit can only be
set (not cleared) in software).
0 = Does not initiate an EEPROM read
DS30430B-page 33
PIC16F8X
EECON1 and EECON2 Registers
EECON1 is the control register with five low order bits
physically implemented. The upper-three bits are
non-existent and read as '0's.
Control bits RD and WR initiate read and write,
respectively. These bits cannot be cleared, only set, in
software. They are cleared in hardware at completion
of the read or write operation. The inability to clear the
WR bit in software prevents the accidental, premature
termination of a write operation.
The WREN bit, when set, will allow a write operation.
On power-up, the WREN bit is clear. The WRERR bit is
set when a write operation is interrupted by a MCLR
reset or a WDT time-out reset during normal operation.
In these situations, following reset, the user can check
the WRERR bit and rewrite the location. The data and
address will be unchanged in the EEDATA and
EEADR registers.
Interrupt flag bit EEIF is set when write is complete. It
must be cleared in software.
EECON2 is not a physical register. Reading EECON2
will read all '0's. The EECON2 register is used
exclusively in the Data EEPROM write sequence.
7.3
Reading the EEPROM Data Memory
To read a data memory location, the user must write the
address to the EEADR register and then set control bit
RD (EECON1<0>). The data is available, in the very
next cycle, in the EEDATA register; therefore it can be
read in the next instruction. EEDATA will hold this value
until another read or until it is written to by the user
(during a write operation).
EXAMPLE 7-1:
BCF
MOVLW
MOVWF
BSF
BSF
BCF
MOVF
DATA EEPROM READ
STATUS, RP0
CONFIG_ADDR
EEADR
STATUS, RP0
EECON1, RD
STATUS, RP0
EEDATA, W
DS30430B-page 34
;
;
;
;
;
;
;
Bank 0
7.4
Writing to the EEPROM Data Memory
To write an EEPROM data location, the user must first
write the address to the EEADR register and the data
to the EEDATA register. Then the user must follow a
specific sequence to initiate the write for each byte.
EXAMPLE 7-2:
Required
Sequence
7.2
DATA EEPROM WRITE
BSF
BCF
BSF
MOVLW
MOVWF
MOVLW
MOVWF
BSF
STATUS, RP0
INTCON, GIE
EECON1, WREN
55h
EECON2
AAh
EECON2
EECON1,WR
BSF
INTCON, GIE
;
;
;
;
;
;
;
;
;
;
Bank 1
Disable INTs.
Enable Write
Write 55h
Write AAh
Set WR bit
begin write
Enable INTs.
The write will not initiate if the above sequence is not
exactly followed (write 55h to EECON2, write AAh to
EECON2, then set WR bit) for each byte. We strongly
recommend that interrupts be disabled during this
code segment.
Additionally, the WREN bit in EECON1 must be set to
enable write. This mechanism prevents accidental
writes to data EEPROM due to errant (unexpected)
code execution (i.e., lost programs). The user should
keep the WREN bit clear at all times, except when
updating EEPROM. The WREN bit is not cleared
by hardware
After a write sequence has been initiated, clearing the
WREN bit will not affect this write cycle. The WR bit will
be inhibited from being set unless the WREN bit is set.
At the completion of the write cycle, the WR bit is
cleared in hardware and the EE Write Complete
Interrupt Flag bit (EEIF) is set. The user can either
enable this interrupt or poll this bit. EEIF must be
cleared by software.
Address to read
Bank 1
EE Read
Bank 0
W = EEDATA
PIC16F8X
7.5
Write Verify
7.6
Depending on the application, good programming
practice may dictate that the value written to the Data
EEPROM should be verified (Example 7-3) to the
desired value to be written. This should be used in
applications where an EEPROM bit will be stressed
near the specification limit. The Total Endurance disk
will help determine your comfort level.
There are conditions when the device may not want to
write to the data EEPROM memory. To protect against
spurious EEPROM writes, various mechanisms have
been built in. On power-up, WREN is cleared. Also, the
Power-up Timer (72 ms duration) prevents
EEPROM write.
The write initiate sequence and the WREN bit together
help prevent an accidental write during brown-out,
power glitch, or software malfunction.
Generally the EEPROM write failure will be a bit which
was written as a '1', but reads back as a '0' (due to
leakage off the bit).
EXAMPLE 7-3:
BCF
:
:
MOVF
BSF
READ
BSF
7.7
WRITE VERIFY
STATUS, RP0 ;
;
;
EEDATA, W
;
STATUS, RP0 ;
Protection Against Spurious Writes
Data EEPROM Operation during Code
Protect
When the device is code protected, the CPU is able to
read and write unscrambled data to the Data
EEPROM.
Bank 0
Any code can go here
Must be in Bank 0
Bank 1
For ROM devices, there are two code protection bits
(Section 8.1). One for the ROM program memory and
one for the Data EEPROM memory.
EECON1, RD
; YES, Read the
;
value written
STATUS, RP0 ; Bank 0
BCF
;
; Is the value written (in W reg) and
;
read (in EEDATA) the same?
;
SUBWF EEDATA, W
;
BTFSS STATUS, Z
; Is difference 0?
GOTO WRITE_ERR
; NO, Write error
:
; YES, Good write
:
; Continue program
TABLE 7-1:
Address
REGISTERS/BITS ASSOCIATED WITH DATA EEPROM
Name
Bit 7
Bit 6
Bit 5
Bit 4
Bit 3
Bit 2
Bit 1
Bit 0
Value on
Power-on
Reset
Value on all
other resets
uuuu uuuu
08h
EEDATA
EEPROM data register
xxxx xxxx
09h
EEADR
EEPROM address register
xxxx xxxx
uuuu uuuu
88h
EECON1
---0 x000
---0 q000
89h
EECON2
---- ----
---- ----
—
—
—
EEPROM control register 2
EEIF
WRERR
WREN
WR
RD
Legend: x = unknown, u = unchanged, - = unimplemented read as '0', q = value depends upon condition. Shaded cells are not
used by Data EEPROM.
DS30430B-page 35
PIC16F8X
NOTES:
DS30430B-page 36
PIC16F8X
8.0
SPECIAL FEATURES OF THE
CPU
What sets a microcontroller apart from other
processors are special circuits to deal with the needs of
real time applications. The PIC16F8X has a host of
such features intended to maximize system reliability,
minimize cost through elimination of external
components, provide power saving operating modes
and offer code protection. These features are:
8.1
Configuration Bits
The configuration bits can be programmed (read as '0')
or left unprogrammed (read as '1') to select various
device configurations. These bits are mapped in
program memory location 2007h.
Address 2007h is beyond the user program memory
space and it belongs to the special test/configuration
memory space (2000h - 3FFFh). This space can only
be accessed during programming.
• OSC Selection
• Reset
- Power-on Reset (POR)
- Power-up Timer (PWRT)
- Oscillator Start-up Timer (OST)
• Interrupts
• Watchdog Timer (WDT)
• SLEEP
• Code protection
• ID locations
• In-circuit serial programming
The PIC16F8X has a Watchdog Timer which can be
shut off only through configuration bits. It runs off its
own RC oscillator for added reliability. There are two
timers that offer necessary delays on power-up. One is
the Oscillator Start-up Timer (OST), intended to keep
the chip in reset until the crystal oscillator is stable. The
other is the Power-up Timer (PWRT), which provides a
fixed delay of 72 ms (nominal) on power-up only. This
design keeps the device in reset while the power
supply stabilizes. With these two timers on-chip, most
applications need no external reset circuitry.
SLEEP mode offers a very low current power-down
mode. The user can wake-up from SLEEP through
external reset, Watchdog Timer time-out or through an
interrupt. Several oscillator options are provided to
allow the part to fit the application. The RC oscillator
option saves system cost while the LP crystal option
saves power. A set of configuration bits are used to
select the various options.
DS30430B-page 37
PIC16F8X
FIGURE 8-1:
R-u
CP
bit13
R-u
CP
CONFIGURATION WORD - PIC16CR83 AND PIC16CR84
R-u
CP
R-u
CP
R-u
CP
R-u
CP
R/P-u
DP
R-u
CP
R-u
CP
R-u
CP
R-u
R-u
R-u
R-u
PWRTE WDTE FOSC1 FOSC0
bit0
R = Readable bit
P = Programmable bit
u = unchanged
bit 13:8 CP: Program Memory Code Protection bit
1 = Code protection off
0 = Program memory is code protected
bit 7
DP: Data Memory Code Protection bit
0 = Data memory is code protected
bit 6:4
CP: Program Memory Code Protection bit
0 = Program memory is code protected
bit 3
PWRTE: Power-up Timer Enable bit
1 = Power-up timer is disabled
0 = Power-up timer is enabled
bit 2
WDTE: Watchdog Timer Enable bit
1 = WDT enabled
0 = WDT disabled
bit 1:0
FOSC1:FOSC0: Oscillator Selection bits
11 = RC oscillator
10 = HS oscillator
01 = XT oscillator
00 = LP oscillator
FIGURE 8-2:
CONFIGURATION WORD - PIC16F83 AND PIC16F84
R/P-u R/P-u R/P-u R/P-u R/P-u R/P-u R/P-u R/P-u R/P-u
CP
CP
CP
CP
CP
CP
CP
CP
CP
bit13
R/P-u
R/P-u
R/P-u R/P-u
R/P-u
CP
PWRTE WDTE FOSC1 FOSC0
bit0
R = Readable bit
P = Programmable bit
u = unchanged
bit 13:4 CP: Code Protection bit
0 = All memory is code protected
bit 3
PWRTE: Power-up Timer Enable bit
1 = Power-up timer is disabled
0 = Power-up timer is enabled
bit 2
WDTE: Watchdog Timer Enable bit
1 = WDT enabled
0 = WDT disabled
bit 1:0
FOSC1:FOSC0: Oscillator Selection bits
11 = RC oscillator
10 = HS oscillator
01 = XT oscillator
00 = LP oscillator
DS30430B-page 38
PIC16F8X
8.2
Oscillator Configurations
8.2.1
OSCILLATOR TYPES
TABLE 8-1:
The PIC16F8X can be operated in four different
oscillator modes. The user can program two
configuration bits (FOSC1 and FOSC0) to select one of
these four modes:
•
•
•
•
LP
XT
HS
RC
Low Power Crystal
Crystal/Resonator
High Speed Crystal/Resonator
Resistor/Capacitor
Ranges Tested:
Mode
Freq
XT
455 kHz
2.0 MHz
4.0 MHz
8.0 MHz
10.0 MHz
HS
Note :
8.2.2
CRYSTAL OSCILLATOR / CERAMIC
RESONATORS
In XT, LP or HS modes a crystal or ceramic resonator
is connected to the OSC1/CLKIN and OSC2/CLKOUT
pins to establish oscillation (Figure 8-3).
FIGURE 8-3:
CRYSTAL/CERAMIC
RESONATOR OPERATION
(HS, XT OR LP OSC
CONFIGURATION)
C1(1)
OSC1
XTAL
RF(3)
OSC2
C2(1)
Note1:
2:
3:
To
internal
logic
PIC16F83/CR83/F84/CR84
CAPACITOR SELECTION
FOR CERAMIC RESONATORS
OSC1/C1
OSC2/C2
47 - 100 pF 47 - 100 pF
15 - 33 pF 15 - 33 pF
15 - 33 pF 15 - 33 pF
15 - 33 pF 15 - 33 pF
15 - 33 pF 15 - 33 pF
Recommended values of C1 and C2 are identical
to the ranges tested table.
Higher capacitance increases the stability of the
oscillator but also increases the start-up time.
These values are for design guidance only. Since
each resonator has its own characteristics, the user
should consult the resonator manufacturer for the
appropriate values of external components.
Resonators Tested:
455 kHz
2.0 MHz
4.0 MHz
8.0 MHz
10.0 MHz
Panasonic EFO-A455K04B
Murata Erie CSA2.00MG
Murata Erie CSA4.00MG
Murata Erie CSA8.00MT
Murata Erie CSA10.00MTZ
± 0.3%
± 0.5%
± 0.5%
± 0.5%
± 0.5%
None of the resonators had built-in capacitors.
SLEEP
RS(2)
PIC16FXX
See Table 8-1 for recommended values of
C1 and C2.
A series resistor (RS) may be required for
AT strip cut crystals.
RF varies with the crystal chosen.
The PIC16F8X oscillator design requires the use of a
parallel cut crystal. Use of a series cut crystal may give
a frequency out of the crystal manufacturers
specifications. When in XT, LP or HS modes, the device
can have an external clock source to drive the
OSC1/CLKIN pin (Figure 8-4).
FIGURE 8-4:
EXTERNAL CLOCK INPUT
OPERATION (HS, XT OR LP
OSC CONFIGURATION)
OSC1
Clock from
ext. system
PIC16FXX
Open
OSC2
DS30430B-page 39
PIC16F8X
TABLE 8-2:
PIC16F83/CR83/F84/CR84
CAPACITOR SELECTION
FOR CRYSTAL OSCILLATOR
Mode
Freq
OSC1/C1
OSC2/C2
LP
32 kHz
200 kHz
100 kHz
2 MHz
4 MHz
4 MHz
10 MHz
68 - 100 pF
15 - 33 pF
100 - 150 pF
15 - 33 pF
15 - 33 pF
15 - 33 pF
15 - 33 pF
68 - 100 pF
15 - 33 pF
100 - 150 pF
15 - 33 pF
15 - 33 pF
15 - 33 pF
15 - 33 pF
XT
HS
Note :
Higher capacitance increases the stability of
oscillator but also increases the start-up time.
These values are for design guidance only. Rs may
be required in HS mode as well as XT mode to
avoid overdriving crystals with low drive level specification. Since each crystal has its own characteristics, the user should consult the crystal
manufacturer for appropriate values of external
components.
For VDD > 4.5V, C1 = C2 ≈ 30 pF is recommended.
Crystals Tested:
32.768 kHz
100 kHz
200 kHz
1.0 MHz
2.0 MHz
4.0 MHz
10.0 MHz
8.2.3
Epson C-001R32.768K-A
Epson C-2 100.00 KC-P
STD XTL 200.000 KHz
ECS ECS-10-13-2
ECS ECS-20-S-2
ECS ECS-40-S-4
ECS ECS-100-S-4
± 20 PPM
± 20 PPM
± 20 PPM
± 50 PPM
± 50 PPM
± 50 PPM
± 50 PPM
EXTERNAL CRYSTAL OSCILLATOR
CIRCUIT
Either a prepackaged oscillator can be used or a simple
oscillator circuit with TTL gates can be built.
Prepackaged oscillators provide a wide operating
range and better stability. A well-designed crystal
oscillator will provide good performance with TTL
gates. Two types of crystal oscillator circuits are
available; one with series resonance, and one with
parallel resonance.
FIGURE 8-5:
EXTERNAL PARALLEL
RESONANT CRYSTAL
OSCILLATOR CIRCUIT
+5V
To Other
Devices
PIC16FXX
10k
74AS04
4.7k
CLKIN
74AS04
10k
XTAL
10k
20 pF
20 pF
Figure 8-6 shows a series resonant oscillator circuit.
This circuit is also designed to use the fundamental
frequency of the crystal. The inverter performs a
180-degree phase shift. The 330 kΩ resistors provide
the negative feedback to bias the inverters in their
linear region.
FIGURE 8-6:
EXTERNAL SERIES
RESONANT CRYSTAL
OSCILLATOR CIRCUIT
330 kΩ
330 kΩ
74AS04
74AS04
To Other
Devices
PIC16FXX
74AS04
CLKIN
0.1 µF
XTAL
Figure 8-5 shows a parallel resonant oscillator circuit.
The circuit is designed to use the fundamental
frequency of the crystal. The 74AS04 inverter performs
the 180-degree phase shift that a parallel oscillator
requires. The 4.7 kΩ resistor provides negative
feedback for stability. The 10 kΩ potentiometer biases
the 74AS04 in the linear region. This could be used for
external oscillator designs.
DS30430B-page 40
PIC16F8X
8.2.4
RC OSCILLATOR
For timing insensitive applications the RC device option
offers additional cost savings. The RC oscillator
frequency is a function of the supply voltage, the
resistor (Rext) values, capacitor (Cext) values, and the
operating temperature. In addition to this, the oscillator
frequency will vary from unit to unit due to normal
process parameter variation. Furthermore, the
difference in lead frame capacitance between package
types also affects the oscillation frequency, especially
for low Cext values. The user needs to take into
account variation due to tolerance of the external
R and C components. Figure 8-7 shows how an R/C
combination is connected to the PIC16F8X. For Rext
values below 2.2 kΩ, the oscillator operation may
become unstable, or stop completely. For very high
Rext values (e.g., 1 MΩ), the oscillator becomes
sensitive to noise, humidity and leakage. Thus, we
recommend keeping Rext between 5 kΩ and 100 kΩ.
Although the oscillator will operate with no external
capacitor (Cext = 0 pF), we recommend using values
above 20 pF for noise and stability reasons. With little
or no external capacitance, the oscillation frequency
can vary dramatically due to changes in external
capacitances, such as PCB trace capacitance or
package lead frame capacitance.
See the electrical specification section for variation of
oscillator frequency due to VDD for given Rext/Cext
values as well as frequency variation due to
operating temperature.
The oscillator frequency, divided by 4, is available on
the OSC2/CLKOUT pin, and can be used for test
purposes or to synchronize other logic (see Figure 3-2
for waveform).
FIGURE 8-7:
RC OSCILLATOR MODE
VDD
Rext
Internal
clock
OSC1
Cext
PIC16FXX
VSS
Fosc/4
Note:
OSC2/CLKOUT
When the device oscillator is in RC mode,
do not drive the OSC1 pin with an external
clock or you may damage the device.
See the electrical specification section for RC
frequency variation from part to part due to normal
process variation. The variation is larger for larger R
(since leakage current variation will affect RC
frequency more for large R) and for smaller C (since
variation of input capacitance has a greater affect on
RC frequency).
DS30430B-page 41
PIC16F8X
8.3
Reset
The PIC16F8X differentiates between various kinds
of reset:
•
•
•
•
•
MCLR reset during normal operation
MCLR reset during SLEEP
WDT Reset (during normal operation)
WDT Wake-up (during SLEEP)
Figure 8-8 shows a simplified block diagram of the
on-chip reset circuit. The MCLR reset path has a noise
filter to ignore small pulses. The electrical specifications state the pulse width requirements for the MCLR
pin.
“reset state” on POR, MCLR or WDT reset during
normal operation and on MCLR reset during SLEEP.
They are not affected by a WDT reset during SLEEP,
since this reset is viewed as the resumption of normal
operation.
Table 8-3 gives a description of reset conditions for the
program counter (PC) and the STATUS register.
Table 8-4 gives a full description of reset states for all
registers.
The TO and PD bits are set or cleared differently in different reset situations (Section 8.7). These bits are
used in software to determine the nature of the reset.
Some registers are not affected in any reset condition;
their status is unknown on a POR reset and unchanged
in any other reset. Most other registers are reset to a
FIGURE 8-8:
SIMPLIFIED BLOCK DIAGRAM OF ON-CHIP RESET CIRCUIT
External
Reset
MCLR
WDT
Module
SLEEP
WDT
Time_Out
Reset
VDD rise
detect
Power_on_Reset
S
10-bit Ripple counter
R
VDD
OST/PWRT
OST
Chip_Reset
Q
OSC1/
CLKIN
PWRT
On-chip
RC OSC(1)
10-bit Ripple counter
Enable PWRT
Note 1: This is a separate oscillator from the
RC oscillator of the CLKIN pin.
DS30430B-page 42
See Table 8-5
Enable OST
PIC16F8X
TABLE 8-3:
RESET CONDITION FOR PROGRAM COUNTER AND THE STATUS REGISTER
Program Counter
Condition
Power-on Reset
000h
STATUS Register
0001 1xxx
MCLR Reset during normal operation
000h
000u uuuu
MCLR Reset during SLEEP
000h
0001 0uuu
000h
0000 1uuu
WDT Wake-up
PC + 1
Interrupt wake-up from SLEEP
PC + 1
uuu0 0uuu
(1)
uuu1 0uuu
Legend: u = unchanged, x = unknown.
Note 1: When the wake-up is due to an interrupt and the GIE bit is set, the PC is loaded with the interrupt vector
(0004h).
TABLE 8-4:
Register
W
RESET CONDITIONS FOR ALL REGISTERS
Address
Power-on Reset
MCLR Reset during:
– normal operation
– SLEEP
WDT Reset during normal operation
Wake-up from SLEEP:
– through interrupt
– through WDT Time-out
—
xxxx xxxx
uuuu uuuu
uuuu uuuu
INDF
00h
---- ----
---- ----
---- ----
TMR0
01h
xxxx xxxx
uuuu uuuu
uuuu uuuu
PCL
02h
0000h
0000h
STATUS
03h
0001 1xxx
000q quuu(3)
uuuq quuu(3)
FSR
04h
xxxx xxxx
uuuu uuuu
uuuu uuuu
PORTA
05h
---x xxxx
---u uuuu
---u uuuu
PORTB
06h
xxxx xxxx
uuuu uuuu
uuuu uuuu
EEDATA
08h
xxxx xxxx
uuuu uuuu
uuuu uuuu
EEADR
09h
xxxx xxxx
uuuu uuuu
uuuu uuuu
PCLATH
0Ah
---0 0000
---0 0000
---u uuuu
INTCON
0Bh
0000 000x
0000 000u
uuuu uuuu(1)
INDF
80h
---- ----
---- ----
---- ----
PC + 1(2)
OPTION
81h
1111 1111
1111 1111
uuuu uuuu
PCL
82h
0000h
0000h
PC + 1
STATUS
83h
0001 1xxx
000q quuu(3)
uuuq quuu(3)
FSR
84h
xxxx xxxx
uuuu uuuu
uuuu uuuu
TRISA
85h
---1 1111
---1 1111
---u uuuu
TRISB
86h
1111 1111
1111 1111
uuuu uuuu
EECON1
88h
---0 x000
---0 q000
---0 uuuu
EECON2
89h
---- ----
---- ----
---- ----
PCLATH
8Ah
---0 0000
---0 0000
---u uuuu
INTCON
8Bh
0000 000x
0000 000u
uuuu uuuu(1)
Legend: u = unchanged, x = unknown, - = unimplemented bit read as '0',
q = value depends on condition.
Note 1: One or more bits in INTCON will be affected (to cause wake-up).
2: When the wake-up is due to an interrupt and the GIE bit is set, the PC is loaded with the interrupt vector
(0004h).
3: Table 8-3 lists the reset value for each specific condition.
DS30430B-page 43
PIC16F8X
8.4
A Power-on Reset pulse is generated on-chip when
VDD rise is detected (in the range of 1.2V - 1.7V). To
take advantage of the POR, just tie the MCLR pin
directly (or through a resistor) to VDD. This will
eliminate external RC components usually needed to
create Power-on Reset. A minimum rise time for VDD
must be met for this to operate properly. See Electrical
Specifications for details.
When the device starts normal operation (exits the
reset condition), device operating parameters (voltage,
frequency, temperature, ...) must be meet to ensure
operation. If these conditions are not met, the device
must be held in reset until the operating conditions
are met.
For additional information, refer to Application Note
AN607, "Power-up Trouble Shooting."
The POR circuit does not produce an internal reset
when VDD declines.
8.5
Power-up Timer (PWRT)
The Power-up Timer (PWRT) provides a fixed 72 ms
nominal time-out (TPWRT) from POR (Figure 8-10,
Figure 8-11, Figure 8-12 and Figure 8-13). The
Power-up Timer operates on an internal RC oscillator.
The chip is kept in reset as long as the PWRT is active.
The PWRT delay allows the VDD to rise to an acceptable level (Possible exception shown in Figure 8-13).
FIGURE 8-9:
EXTERNAL POWER-ON
RESET CIRCUIT (FOR SLOW
VDD POWER-UP)
VDD
VDD
D
R
R1
MCLR
C
PIC16FXX
Note 1: External Power-on Reset circuit is
required only if VDD power-up rate is too
slow. The diode D helps discharge the
capacitor quickly when VDD powers down.
2: R < 40 kΩ is recommended to make sure
that voltage drop across R does not exceed
0.2V (max leakage current spec on MCLR
pin is 5 µA). A larger voltage drop will
degrade VIH level on the MCLR pin.
3: R1 = 100Ω to 1 kΩ will limit any current
flowing into MCLR from external
capacitor C in the event of an MCLR pin
breakdown due to ESD or EOS.
A configuration bit, PWRTE, can enable/disable the
PWRT. See either Figure 8-1 or Figure 8-2 for the operation of the PWRTE bit for a particular device.
The power-up time delay TPWRT will vary from chip to
chip due to VDD, temperature, and process variation.
See DC parameters for details.
8.6
Oscillator Start-up Timer (OST)
The Oscillator Start-up Timer (OST) provides a 1024
oscillator cycle delay (from OSC1 input) after the
PWRT delay ends (Figure 8-10, Figure 8-11,
Figure 8-12 and Figure 8-13). This ensures the crystal
oscillator or resonator has started and stabilized.
The OST time-out (TOST) is invoked only for XT, LP and
HS modes and only on Power-on Reset or wake-up
from SLEEP.
When VDD rises very slowly, it is possible that the
TPWRT time-out and TOST time-out will expire before
VDD has reached its final value. In this case
(Figure 8-13), an external power-on reset circuit may
be necessary (Figure 8-9).
DS30430B-page 44
PIC16F8X
FIGURE 8-10: TIME-OUT SEQUENCE ON POWER-UP (MCLR NOT TIED TO VDD): CASE 1
VDD
MCLR
INTERNAL POR
TPWRT
PWRT TIME-OUT
TOST
OST TIME-OUT
INTERNAL RESET
FIGURE 8-11: TIME-OUT SEQUENCE ON POWER-UP (MCLR NOT TIED TO VDD): CASE 2
VDD
MCLR
INTERNAL POR
TPWRT
PWRT TIME-OUT
TOST
OST TIME-OUT
INTERNAL RESET
DS30430B-page 45
PIC16F8X
FIGURE 8-12: TIME-OUT SEQUENCE ON POWER-UP (MCLR TIED TO VDD): FAST VDD RISE TIME
VDD
MCLR
INTERNAL POR
TPWRT
PWRT TIME-OUT
TOST
OST TIME-OUT
INTERNAL RESET
FIGURE 8-13: TIME-OUT SEQUENCE ON POWER-UP (MCLR TIED TO VDD): SLOW VDD RISE TIME
V1
VDD
MCLR
INTERNAL POR
TPWRT
PWRT TIME-OUT
TOST
OST TIME-OUT
INTERNAL RESET
When VDD rises very slowly, it is possible that the TPWRT time-out and TOST time-out will expire before VDD
has reached its final value. In this example, the chip will reset properly if, and only if, V1 ≥ VDD min.
DS30430B-page 46
PIC16F8X
8.7
Time-out Sequence and Power-down
Status Bits (TO/PD)
On power-up (Figure 8-10, Figure 8-11, Figure 8-12
and Figure 8-13) the time-out sequence is as follows:
First PWRT time-out is invoked after a POR has
expired. Then the OST is activated. The total time-out
will vary based on oscillator configuration and PWRTE
configuration bit status. For example, in RC mode with
the PWRT disabled, there will be no time-out at all.
TABLE 8-5:
XT, HS, LP
RC
Power-up
PWRT
PWRT
Enabled
Disabled
72 ms +
1024TOSC
1024TOSC
72 ms
—
Wake-up
from
SLEEP
PD
1
0
x
0
0
1
1
1
x
0
1
0
1
0
To reset a PIC16F8X device when a brown-out occurs,
external brown-out protection circuits may be built, as
shown in Figure 8-14 and Figure 8-15.
VDD
VDD
33k
10k
—
Table 8-6 shows the significance of the TO and PD bits.
Table 8-3 lists the reset conditions for some special
registers, while Table 8-4 lists the reset conditions for
all the registers.
TO
A brown-out is a condition where device power (VDD)
dips below its minimum value, but not to zero, and
then recovers. The device should be reset in the event
of a brown-out.
1024TOSC
Since the time-outs occur from the POR reset pulse, if
MCLR is kept low long enough, the time-outs will
expire. Then bringing MCLR high, execution will begin
immediately (Figure 8-10). This is useful for testing
purposes or to synchronize more than one PIC16F8X
device when operating in parallel.
TABLE 8-6:
Reset on Brown-Out
FIGURE 8-14: BROWN-OUT PROTECTION
CIRCUIT 1
TIME-OUT IN VARIOUS
SITUATIONS
Oscillator
Configuration
8.8
STATUS BITS AND THEIR
SIGNIFICANCE
40k
FIGURE 8-15: BROWN-OUT PROTECTION
CIRCUIT 2
VDD
VDD
R1
Q1
MCLR
R2
40k
PIC16F8X
This brown-out circuit is less expensive, although less
accurate. Transistor Q1 turns off when VDD is below a
certain level such that:
VDD •
PIC16F8X
This circuit will activate reset when VDD goes below
(Vz + 0.7V) where Vz = Zener voltage.
Condition
Power-on Reset
Illegal, TO is set on POR
Illegal, PD is set on POR
WDT Wake-up
MCLR Reset during normal operation
MCLR Reset during SLEEP or interrupt
wake-up from SLEEP
MCLR
R1
R1 + R2
= 0.7V
DS30430B-page 47
PIC16F8X
8.9
Interrupts
The PIC16F8X has 4 sources of interrupt:
•
•
•
•
External interrupt RB0/INT pin
TMR0 overflow interrupt
PORTB change interrupts (pins RB7:RB4)
Data EEPROM write complete interrupt
The interrupt control register (INTCON) records
individual interrupt requests in flag bits. It also contains
the individual and global interrupt enable bits.
The global interrupt enable bit, GIE (INTCON<7>)
enables (if set) all un-masked interrupts or disables (if
cleared) all interrupts. Individual interrupts can be
disabled through their corresponding enable bits in
INTCON register. Bit GIE is cleared on reset.
The “return from interrupt” instruction, RETFIE, exits
interrupt routine as well as sets the GIE bit, which
re-enable interrupts.
When an interrupt is responded to; the GIE bit is
cleared to disable any further interrupt, the return
address is pushed onto the stack and the PC is loaded
with 0004h. For external interrupt events, such as the
RB0/INT pin or PORTB change interrupt, the interrupt
latency will be three to four instruction cycles. The
exact latency depends when the interrupt event occurs
(Figure 8-17). The latency is the same for both one and
two cycle instructions. Once in the interrupt service routine the source(s) of the interrupt can be determined by
polling the interrupt flag bits. The interrupt flag bit(s)
must be cleared in software before re-enabling
interrupts to avoid infinite interrupt requests.
Note 1: Individual interrupt flag bits are set
regardless of the status of their
corresponding mask bit or the GIE bit.
The RB0/INT pin interrupt, the RB port change interrupt
and the TMR0 overflow interrupt flags are contained in
the INTCON register.
FIGURE 8-16: INTERRUPT LOGIC
T0IF
T0IE
INTF
INTE
Wake-up
(If in SLEEP mode)
Interrupt to CPU
RBIF
RBIE
EEIF
EEIE
GIE
DS30430B-page 48
PIC16F8X
FIGURE 8-17: INT PIN INTERRUPT TIMING
Q1
Q2
Q3
Q4
Q1
Q2
Q3
Q4
Q1
Q2
Q3
Q4
Q1
Q2
Q3
Q4
Q1
Q2
Q3
Q4
OSC1
CLKOUT 3
4
INT pin
1
1
INTF flag
(INTCON<1>)
Interrupt Latency 2
5
GIE bit
(INTCON<7>)
INSTRUCTION FLOW
PC
PC
Instruction
fetched
Inst (PC)
Instruction
executed
Inst (PC-1)
PC+1
Inst (PC+1)
Inst (PC)
0004h
PC+1
—
Dummy Cycle
0005h
Inst (0004h)
Inst (0005h)
Dummy Cycle
Inst (0004h)
Note 1: INTF flag is sampled here (every Q1).
2: Interrupt latency = 3-4Tcy where Tcy = instruction cycle time.
Latency is the same whether Inst (PC) is a single cycle or a 2-cycle instruction.
3: CLKOUT is available only in RC oscillator mode.
4: For minimum width of INT pulse, refer to AC specs.
5: INTF is enabled to be set anytime during the Q4-Q1 cycles.
8.9.1
INT INTERRUPT
External interrupt on RB0/INT pin is edge triggered:
either rising if INTEDG bit (OPTION<6>) is set, or
falling, if INTEDG bit is clear. When a valid edge
appears on the RB0/INT pin, the INTF bit
(INTCON<1>) is set. This interrupt can be disabled by
clearing control bit INTE (INTCON<4>). Flag bit INTF
must be cleared in software via the interrupt service
routine before re-enabling this interrupt. The INT
interrupt can wake the processor from SLEEP
(Section 8.12) only if the INTE bit was set prior to going
into SLEEP. The status of the GIE bit decides whether
the processor branches to the interrupt vector
following wake-up.
8.9.2
8.9.3
PORT RB INTERRUPT
An input change on PORTB<7:4> sets flag bit RBIF
(INTCON<0>). The interrupt can be enabled/disabled
by setting/clearing enable bit RBIE (INTCON<3>)
(Section 5.2).
Note 1: For a change on the I/O pin to be
recognized, the pulse width must be at
least TCY wide.
TMR0 INTERRUPT
An overflow (FFh → 00h) in TMR0 will set flag bit T0IF
(INTCON<2>). The interrupt can be enabled/disabled
by setting/clearing enable bit T0IE (INTCON<5>)
(Section 6.0).
DS30430B-page 49
PIC16F8X
8.10
Context Saving During Interrupts
During an interrupt, only the return PC value is saved
on the stack. Typically, users wish to save key register
values during an interrupt (e.g., W register and
STATUS register). This is implemented in software.
Example 8-1 stores and restores the STATUS and W
register’s values. The User defined registers, W_TEMP
and STATUS_TEMP are the temporary storage
locations for the W and STATUS registers values.
Example 8-1 does the following:
a)
b)
c)
d)
e)
Stores the W register.
Stores the STATUS register in STATUS_TEMP.
Executes the Interrupt Service Routine code.
Restores the STATUS (and bank select bit)
register.
Restores the W register.
EXAMPLE 8-1:
PUSH
ISR
POP
SAVING STATUS AND W REGISTERS IN RAM
MOVWF
SWAPF
MOVWF
:
:
:
:
SWAPF
W_TEMP
STATUS, W
STATUS_TEMP
MOVWF
STATUS
SWAPF
SWAPF
W_TEMP, F
W_TEMP, W
DS30430B-page 50
STATUS_TEMP, W
;
;
;
:
;
;
;
;
;
;
;
;
;
Copy W to TEMP register,
Swap status to be saved into W
Save status to STATUS_TEMP register
Interrupt Service Routine
should configure Bank as required
Swap nibbles in STATUS_TEMP register
and place result into W
Move W into STATUS register
(sets bank to original state)
Swap nibbles in W_TEMP and place result in W_TEMP
Swap nibbles in W_TEMP and place result into W
PIC16F8X
8.11
Watchdog Timer (WDT)
part (see DC specs). If longer time-out periods are
desired, a prescaler with a division ratio of up to 1:128
can be assigned to the WDT under software control by
writing to the OPTION register. Thus, time-out periods
up to 2.3 seconds can be realized.
The Watchdog Timer is a free running on-chip RC
oscillator which does not require any external
components. This RC oscillator is separate from the
RC oscillator of the OSC1/CLKIN pin. That means that
the WDT will run even if the clock on the OSC1/CLKIN
and OSC2/CLKOUT pins of the device has been
stopped, for example, by execution of a SLEEP
instruction. During normal operation a WDT time-out
generates a device RESET. If the device is in SLEEP
mode, a WDT Wake-up causes the device to wake-up
and continue with normal operation. The WDT can be
permanently disabled by programming configuration bit
WDTE as a '0' (Section 8.1).
8.11.1
The CLRWDT and SLEEP instructions clear the WDT
and the postscaler (if assigned to the WDT) and prevent it from timing out and generating a device
RESET condition.
The TO bit in the STATUS register will be cleared upon
a WDT time-out.
8.11.2
WDT PROGRAMMING CONSIDERATIONS
It should also be taken into account that under worst
case conditions (VDD = Min., Temperature = Max., max.
WDT prescaler) it may take several seconds before a
WDT time-out occurs.
WDT PERIOD
The WDT has a nominal time-out period of 18 ms, (with
no prescaler). The time-out periods vary with
temperature, VDD and process variations from part to
FIGURE 8-18: WATCHDOG TIMER BLOCK DIAGRAM
From TMR0 Clock Source
(Figure 6-6)
0
WDT Timer
•
1
M
U
X
Postscaler
8
8 - to -1 MUX
PS2:PS0
•
To TMR0 (Figure 6-6)
PSA
WDT
Enable Bit
1
0
MUX
PSA
WDT
Time-out
Note: PSA and PS2:PS0 are bits in the OPTION register.
TABLE 8-7:
SUMMARY OF REGISTERS ASSOCIATED WITH THE WATCHDOG TIMER
Address
Name
2007h
Config. bits
81h
OPTION
Bit 7
Bit 6
Bit 5
Bit 4
Bit 3
Bit 2
Bit 1
Bit 0
Value on
Power-on
Reset
(2)
(2)
(2)
(2)
PWRTE(1)
WDTE
FOSC1
FOSC0
(2)
RBPU
INTEDG
T0CS
T0SE
PSA
PS2
PS1
PS0
1111 1111
Value on all
other resets
1111 1111
Legend: x = unknown. Shaded cells are not used by the WDT.
Note 1: See Figure 8-1 and Figure 8-2 for operation of the PWRTE bit.
2: See Figure 8-1, Figure 8-2 and Section 8.13 for operation of the Code and Data protection bits.
DS30430B-page 51
PIC16F8X
8.12
Power-down Mode (SLEEP)
8.12.2
A device may be powered down (SLEEP) and later
powered up (Wake-up from SLEEP).
8.12.1
SLEEP
The Power-down mode is entered by executing the
SLEEP instruction.
If enabled, the Watchdog Timer is cleared (but keeps
running), the PD bit (STATUS<3>) is cleared, the TO bit
(STATUS<4>) is set, and the oscillator driver is turned
off. The I/O ports maintain the status they had before
the SLEEP instruction was executed (driving high, low,
or hi-impedance).
For the lowest current consumption in SLEEP mode,
place all I/O pins at either at VDD or VSS, with no
external circuitry drawing current from the I/O pins, and
disable external clocks. I/O pins that are hi-impedance
inputs should be pulled high or low externally to avoid
switching currents caused by floating inputs. The
T0CKI input should also be at VDD or VSS. The
contribution from on-chip pull-ups on PORTB should
be considered.
The MCLR pin must be at a logic high level (VIHMC).
It should be noted that a RESET generated by a WDT
time-out does not drive the MCLR pin low.
WAKE-UP FROM SLEEP
The device can wake-up from SLEEP through one of
the following events:
1.
2.
3.
External reset input on MCLR pin.
WDT Wake-up (if WDT was enabled).
Interrupt from RB0/INT pin, RB port change, or
data EEPROM write complete.
Peripherals cannot generate interrupts during SLEEP,
since no on-chip Q clocks are present.
The first event (MCLR reset) will cause a device reset.
The two latter events are considered a continuation of
program execution. The TO and PD bits can be used to
determine the cause of a device reset. The PD bit,
which is set on power-up, is cleared when SLEEP is
invoked. The TO bit is cleared if a WDT time-out
occurred (and caused wake-up).
While the SLEEP instruction is being executed, the next
instruction (PC + 1) is pre-fetched. For the device to
wake-up through an interrupt event, the corresponding
interrupt enable bit must be set (enabled). Wake-up
occurs regardless of the state of the GIE bit. If the GIE
bit is clear (disabled), the device continues execution at
the instruction after the SLEEP instruction. If the GIE bit
is set (enabled), the device executes the instruction
after the SLEEP instruction and then branches to the
interrupt address (0004h). In cases where the
execution of the instruction following SLEEP is not
desirable, the user should have a NOP after the
SLEEP instruction.
FIGURE 8-19: WAKE-UP FROM SLEEP THROUGH INTERRUPT
Q1 Q2 Q3 Q4
Q1 Q2 Q3 Q4
Q1
Q1 Q2 Q3 Q4
Q1 Q2 Q3 Q4
Q1 Q2 Q3 Q4
Q1 Q2 Q3
Q4
OSC1
TOST(2)
CLKOUT(4)
INT pin
INTF flag
(INTCON<1>)
Interrupt Latency
(Note 2)
GIE bit
(INTCON<7>)
Processor in
SLEEP
INSTRUCTION FLOW
PC
Instruction
fetched
Instruction
executed
Note
1:
2:
3:
4:
PC
Inst(PC) = SLEEP
Inst(PC - 1)
PC+1
PC+2
PC+2
Inst(PC + 1)
Inst(PC + 2)
SLEEP
Inst(PC + 1)
PC + 2
Dummy cycle
0004h
0005h
Inst(0004h)
Inst(0005h)
Dummy cycle
Inst(0004h)
XT, HS or LP oscillator mode assumed.
TOST = 1024TOSC (drawing not to scale) This delay will not be there for RC osc mode.
GIE = '1' assumed. In this case after wake- up, the processor jumps to the interrupt routine. If GIE = '0', execution will continue in-line.
CLKOUT is not available in these osc modes, but shown here for timing reference.
DS30430B-page 52
PIC16F8X
8.12.3
WAKE-UP USING INTERRUPTS
When global interrupts are disabled (GIE cleared) and
any interrupt source has both its interrupt enable bit
and interrupt flag bit set, one of the following will occur:
• If the interrupt occurs before the execution of a
SLEEP instruction, the SLEEP instruction will complete as a NOP. Therefore, the WDT and WDT
postscaler will not be cleared, the TO bit will not
be set and PD bits will not be cleared.
• If the interrupt occurs during or after the execution of a SLEEP instruction, the device will immediately wake up from sleep. The SLEEP instruction
will be completely executed before the wake-up.
Therefore, the WDT and WDT postscaler will be
cleared, the TO bit will be set and the PD bit will
be cleared.
Even if the flag bits were checked before executing a
SLEEP instruction, it may be possible for flag bits to
become set before the SLEEP instruction completes. To
determine whether a SLEEP instruction executed, test
the PD bit. If the PD bit is set, the SLEEP instruction was
executed as a NOP.
To ensure that the WDT is cleared, a CLRWDT instruction should be executed before a SLEEP instruction.
8.13
Program Verification/Code Protection
If the code protection bit(s) have not been
programmed, the on-chip program memory can be
read out for verification purposes.
Note:
8.14
Microchip does not recommend code protecting widowed devices.
ID Locations
Four memory locations (2000h - 2003h) are designated
as ID locations to store checksum or other code
identification numbers. These locations are not
accessible during normal execution but are readable
and writable only during program/verify. Only the
4 least significant bits of ID location are usable.
For ROM devices, these values are submitted along
with the ROM code.
8.15
In-Circuit Serial Programming
PIC16F8X
microcontrollers
can
be
serially
programmed while in the end application circuit. This is
simply done with two lines for clock and data, and three
other lines for power, ground, and the programming
voltage. Customers can manufacture boards with
unprogrammed devices, and then program the
microcontroller just before shipping the product,
allowing the most recent firmware or custom firmware
to be programmed.
The device is placed into a program/verify mode by
holding the RB6 and RB7 pins low, while raising the
MCLR pin from VIL to VIHH (see programming
specification). RB6 becomes the programming clock
and RB7 becomes the programming data. Both RB6
and RB7 are Schmitt Trigger inputs in this mode.
After reset, to place the device into programming/verify
mode, the program counter (PC) points to location 00h.
A 6-bit command is then supplied to the device, 14-bits
of program data is then supplied to or from the device,
using load or read-type instructions. For complete
details of serial programming, please refer to the
PIC16CXX Programming Specifications (Literature
#DS30189).
FIGURE 8-20: TYPICAL IN-SYSTEM SERIAL
PROGRAMMING
CONNECTION
External
Connector
Signals
To Normal
Connections
PIC16FXX
+5V
VDD
0V
VSS
VPP
MCLR/VPP
CLK
RB6
Data I/O
RB7
VDD
To Normal
Connections
For ROM devices, both the program memory and Data
EEPROM memory may be read, but only the Data
EEPROM memory may be programmed.
DS30430B-page 53
PIC16F8X
NOTES:
DS30430B-page 54
PIC16F8X
9.0
INSTRUCTION SET SUMMARY
Each PIC16FXX instruction is a 14-bit word divided into
an OPCODE which specifies the instruction type and
one or more operands which further specify the operation of the instruction. The PIC16FXX instruction set
summary in Table 9-2 lists byte-oriented, bit-oriented,
and literal and control operations. Table 9-1 shows the
opcode field descriptions.
Byte-oriented instructions: 'f' represents a file
register designator and 'd' represents a destination
designator. The file register designator specifies which
file register is to be used by the instruction.
The destination designator specifies where the result of
the operation is to be placed. If 'd' is 0, the result is
placed in the W register. If 'd' is 1, the result is placed in
the file register specified by the instruction.
Bit-oriented instructions: 'b' represents a bit field
designator which selects the number of the bit affected
by the operation, while 'f' represents the address of the
file in which the bit is located.
Literal and control operations: 'k' represents an eight
or eleven bit constant or literal value.
TABLE 9-1:
OPCODE FIELD
DESCRIPTIONS
Field
Description
f
Register file address (0x00 to 0x7F)
W
Working register (accumulator)
b
Bit address within an 8-bit file register
k
Literal field, constant data or label
x
Don't care location (= 0 or 1)
The assembler will generate code with x = 0. It is the
recommended form of use for compatibility with all
Microchip software tools.
d
Destination select; d = 0: store result in W,
d = 1: store result in file register f.
Default is d = 1
label Label name
TOS
Top of Stack
PC
Program Counter
The instruction set is highly orthogonal and is grouped
into three basic categories:
• Byte-oriented
• Bit-oriented
• Literal and control
All instructions are executed within a single instruction
cycle, unless a conditional test is true or the program
counter is changed as a result of the instruction. The
execution takes two instruction cycles with the second
cycle executed as a NOP. Each cycle consists of four
oscillator periods. Thus, for an oscillator frequency of
4 MHz, the normal instruction execution time is 1 µs.
The instruction execution time is 2 µs for program
branches.
Table 9-2 lists the instructions
Microchip’s assembler (MPASM).
Global Interrupt Enable bit
WDT
Watchdog Timer/Counter
TO
Time-out bit
PD
Power-down bit
Note:
To maintain upward compatibility with
future PIC16FXX products, do not use the
OPTION and TRIS instructions.
All examples use the following format to represent a
hexadecimal number:
0xhh
where h signifies a hexadecimal digit.
FIGURE 9-1:
GENERAL FORMAT FOR
INSTRUCTIONS
Byte-oriented file register operations
13
8 7 6
OPCODE
d
f (FILE #)
0
d = 0 for destination W
d = 1 for destination f
f = 7-bit file register address
Bit-oriented file register operations
13
10 9
7 6
OPCODE
b (BIT #)
f (FILE #)
0
b = 3-bit bit address
f = 7-bit file register address
Literal and control operations
General
13
8
7
OPCODE
dest Destination (Either the W register or the specified
register file location)
0
k (literal)
k = 8-bit immediate value
[ ]
Options
( )
Contents
→
Assigned to
<>
Register bit field
OPCODE
In the set of
k = 11-bit immediate value
∈
by
Figure 9-1 shows the three general formats of
instructions.
PCLATH Program Counter High Latch
GIE
recognized
CALL and GOTO instructions only
13
11
10
0
k (literal)
italics User defined term (font is courier)
DS30430B-page 55
PIC16F8X
TABLE 9-2:
INSTRUCTION SET SUMMARY
Mnemonic,
Operands
ADDWF
ANDWF
CLRF
CLRW
COMF
DECF
DECFSZ
INCF
INCFSZ
IORWF
MOVF
MOVWF
NOP
RLF
RRF
SUBWF
SWAPF
XORWF
Description
Cycles
14-Bit Opcode
MSb
f, d
f, d
f
f, d
f, d
f, d
f, d
f, d
f, d
f, d
f
f, d
f, d
f, d
f, d
f, d
Add W and f
AND W with f
Clear f
Clear W
Complement f
Decrement f
Decrement f, Skip if 0
Increment f
Increment f, Skip if 0
Inclusive OR W with f
Move f
Move W to f
No Operation
Rotate left f through carry
Rotate right f through carry
Subtract W from f
Swap nibbles in f
Exclusive OR W with f
LSb
Status
Affected
Notes
1
1
1
1
1
1
1(2)
1
1(2)
1
1
1
1
1
1
1
1
1
00
00
00
00
00
00
00
00
00
00
00
00
00
00
00
00
00
00
0111
0101
0001
0001
1001
0011
1011
1010
1111
0100
1000
0000
0000
1101
1100
0010
1110
0110
dfff
dfff
lfff
0000
dfff
dfff
dfff
dfff
dfff
dfff
dfff
lfff
0xx0
dfff
dfff
dfff
dfff
dfff
ffff
ffff
ffff
0011
ffff
ffff
ffff
ffff
ffff
ffff
ffff
ffff
0000
ffff
ffff
ffff
ffff
ffff
C,DC,Z
Z
Z
Z
Z
Z
None
Z
None
Z
Z
None
None
C
C
C,DC,Z
None
Z
1,2
1,2
2
1
1
1 (2)
1 (2)
01
01
01
01
00bb
01bb
10bb
11bb
bfff
bfff
bfff
bfff
ffff
ffff
ffff
ffff
None
None
None
None
1,2
1,2
3
3
1
1
2
1
2
1
1
2
2
2
1
1
1
11
11
10
00
10
11
11
00
11
00
00
11
11
111x
1001
0kkk
0000
1kkk
1000
00xx
0000
01xx
0000
0000
110x
1010
kkkk
kkkk
kkkk
0110
kkkk
kkkk
kkkk
0000
kkkk
0000
0110
kkkk
kkkk
kkkk
kkkk
kkkk
0100
kkkk
kkkk
kkkk
1001
kkkk
1000
0011
kkkk
kkkk
C,DC,Z
Z
1,2
1,2
1,2,3
1,2
1,2,3
1,2
1,2
1,2
1,2
1,2
1,2
1,2
BIT-ORIENTED FILE REGISTER OPERATIONS
BCF
BSF
BTFSC
BTFSS
f, b
f, b
f, b
f, b
Bit Clear f
Bit Set f
Bit Test f, Skip if Clear
Bit Test f, Skip if Set
LITERAL AND CONTROL OPERATIONS
ADDLW
ANDLW
CALL
CLRWDT
GOTO
IORLW
MOVLW
RETFIE
RETLW
RETURN
SLEEP
SUBLW
XORLW
k
k
k
k
k
k
k
k
k
Add literal and W
AND literal with W
Call subroutine
Clear Watchdog Timer
Go to address
Inclusive OR literal with W
Move literal to W
Return from interrupt
Return with literal in W
Return from subroutine
Go into standby mode
Subtract W from literal
Exclusive OR literal with W
TO,PD
None
Z
None
None
None
None
TO,PD
C,DC,Z
Z
Note 1: When an I/O register is modified as a function of itself (i.e., MOVF PORTB, 1), the value used will be that value present on
the pins themselves. For example, if the data latch is '1' for a pin configured as input and is driven low by an external
device, the data will be written back with a '0'.
2: If this instruction is executed on the TMR0 register (and, where applicable, d = 1), the prescaler will be cleared if assigned
to the TMR0.
3: If Program Counter (PC) is modified or a conditional test is true, the instruction requires two cycles. The second cycle is
executed as a NOP.
DS30430B-page 56
PIC16F8X
9.1
Instruction Descriptions
ANDLW
AND Literal with W
Syntax:
[ label ] ANDLW
0 ≤ k ≤ 255
Operands:
0 ≤ k ≤ 255
(W) + k → (W)
Operation:
(W) .AND. (k) → (W)
C, DC, Z
Status Affected:
Z
ADDLW
Add Literal and W
Syntax:
[ label ] ADDLW
Operands:
Operation:
Status Affected:
Encoding:
11
k
111x
kkkk
kkkk
Encoding:
11
Description:
The contents of the W register are
added to the eight bit literal 'k' and the
result is placed back in the W register.
Description:
Words:
1
Words:
1
1
Cycles:
1
Cycles:
Example
ADDLW
=
=
ADDWF
Add W and f
Syntax:
[ label ] ADDWF
Operands:
ANDLW
=
0xA3
After Instruction
W
0x25
=
0x03
ANDWF
AND W with f
Syntax:
[ label ] ANDWF
0 ≤ f ≤ 127
d ∈ [0,1]
Operands:
0 ≤ f ≤ 127
d ∈ [0,1]
Operation:
(W) + (f) → (dest)
Operation:
(W) .AND. (f) → (dest)
Status Affected:
C, DC, Z
Status Affected:
Z
Encoding:
00
kkkk
0x5F
W
0x10
After Instruction
W
kkkk
Before Instruction
Before Instruction
W
1001
The contents of W register is AND’ed
with the eight bit literal 'k'. The result is
placed back in the W register.
Example
0x15
k
f,d
0111
dfff
ffff
Encoding:
00
f,d
0101
dfff
ffff
Description:
Add the contents of the W register to
register 'f'. If 'd' is 0 the result is
stored in the W register. If 'd' is 1 the
result is stored back in register 'f'.
Description:
AND the W register with register 'f'. If
'd' is 0 the result is stored in the W
register. If 'd' is 1 the result is stored
back in register 'f'.
Words:
1
Words:
1
Cycles:
1
Cycles:
1
Example
ADDWF
FSR, 0
Before Instruction
W =
FSR =
ANDWF
FSR, 1
Before Instruction
0x17
0xC2
After Instruction
W =
FSR =
Example
W =
FSR =
0x17
0xC2
After Instruction
0xD9
0xC2
W =
FSR =
0x17
0x02
DS30430B-page 57
PIC16F8X
BCF
Bit Clear f
BTFSC
Bit Test f, Skip if Clear
Syntax:
[ label ] BCF
Syntax:
[ label ] BTFSC f,b
Operands:
0 ≤ f ≤ 127
0≤b≤7
Operands:
0 ≤ f ≤ 127
0≤b≤7
Operation:
0 → (f<b>)
Operation:
skip if (f<b>) = 0
Status Affected:
None
Status Affected:
None
Encoding:
01
f,b
00bb
bfff
ffff
Description:
Bit 'b' in register 'f' is cleared.
Words:
1
Cycles:
1
Example
BCF
Encoding:
FLAG_REG = 0x47
bfff
ffff
Words:
1
Cycles:
1(2)
Before Instruction
FLAG_REG = 0xC7
10bb
Description:
FLAG_REG,7
After Instruction
01
If bit 'b' in register 'f' is 0 then the next
instruction is skipped.
If bit 'b' is 0 then the next instruction
fetched during the current instruction
execution is discarded, and a NOP is
executed instead, making this a 2 cycle
instruction.
Example
HERE
FALSE
TRUE
BTFSC
GOTO
•
•
•
FLAG,1
PROCESS_CODE
Before Instruction
PC =
address HERE
After Instruction
if FLAG<1>=0,
PC=address
if FLAG<1>=1,
PC=address
BSF
Bit Set f
Syntax:
[ label ] BSF
Operands:
0 ≤ f ≤ 127
0≤b≤7
Operation:
1 → (f<b>)
Status Affected:
None
Encoding:
01
01bb
bfff
Bit 'b' in register 'f' is set.
Words:
1
Cycles:
1
BSF
FALSE
f,b
Description:
Example
TRUE
FLAG_REG,
ffff
7
Before Instruction
FLAG_REG= 0x0A
After Instruction
FLAG_REG= 0x8A
DS30430B-page 58
PIC16F8X
BTFSS
Bit Test f, skip if Set
CLRF
Clear f
Syntax:
[ label ] BTFSS f,b
Syntax:
[ label ] CLRF
Operands:
0 ≤ f ≤ 127
0≤b<7
Operands:
0 ≤ f ≤ 127
Operation:
00h → (f)
1→Z
Status Affected:
Z
Operation:
skip if (f<b>) = 1
Status Affected:
None
Encoding:
Description:
01
11bb
bfff
ffff
If bit 'b' in register 'f' is 1 then the next
instruction is skipped.
If bit 'b' is 1, then the next instruction
fetched during the current instruction
execution, is discarded and a NOP is
executed instead, making this a 2 cycle
instruction.
Words:
1
Cycles:
1(2)
Example
HERE
FALSE
TRUE
Encoding:
00
f
0001
1fff
ffff
Description:
The contents of register 'f' are cleared
and the Z bit is set.
Words:
1
Cycles:
1
Example
CLRF
FLAG_REG
Before Instruction
FLAG_REG
BTFSC
GOTO
•
•
•
=
0x5A
=
=
0x00
1
After Instruction
FLAG,1
PROCESS_CODE
FLAG_REG
Z
Before Instruction
PC =
address HERE
After Instruction
if FLAG<1>=0,
PC=address
if FLAG<1>=1,
PC=address
FALSE
TRUE
CALL
Subroutine Call
CLRW
Clear W Register
Syntax:
[ label ] CALL k
Syntax:
[ label ] CLRW
Operands:
0 ≤ k ≤ 2047
Operands:
None
Operation:
(PC)+ 1→ TOS,
k → (PC<10:0>),
(PCLATH<4:3>) → (PC<12:11>)
Operation:
00h → (W)
1→Z
Status Affected:
Z
Status Affected:
None
Encoding:
Encoding:
Description:
10
kkkk
kkkk
Subroutine call. First, return address
(PC+1) is pushed onto the stack. The
eleven bit immediate address is loaded
into PC bits <10:0>. The upper bits of
the PC are loaded from PCLATH.
CALL is a two cycle instruction.
Words:
1
Cycles:
2
Example
0kkk
Description:
00
0000
0011
W register is cleared. Zero bit (Z) is
set.
Words:
1
Cycles:
1
Example
0001
CLRW
Before Instruction
W
HERE
CALL
THERE
Before Instruction
PC =
=
0x5A
After Instruction
W
Z
=
=
0x00
1
Address HERE
After Instruction
PC =
TOS =
Address THERE
Address HERE
DS30430B-page 59
PIC16F8X
CLRWDT
Clear Watchdog Timer
DECF
Decrement f
Syntax:
[ label ] CLRWDT
Syntax:
[ label ] DECF f,d
Operands:
None
Operands:
Operation:
00h → WDT
0 → WDT prescaler,
1 → TO
1 → PD
0 ≤ f ≤ 127
d ∈ [0,1]
Operation:
(f) – 1 → (dest)
Status Affected:
Z
Status Affected:
Encoding:
Description:
Encoding:
TO, PD
00
0000
0110
0100
The CLRWDT instruction resets the
watchdog timer. It also resets the
prescaler of the WDT. Status bits TO
and PD are set.
Words:
1
Cycles:
1
Example
Description:
00
0011
dfff
ffff
Decrement register 'f'. If 'd' is 0 the
result is stored in the W register. If 'd'
is 1 the result is stored back in register
'f'.
Words:
1
Cycles:
1
Example
DECF
CNT,
1
Before Instruction
CLRWDT
CNT
Z
Before Instruction
WDT counter =
COMF
Complement f
Syntax:
[ label ] COMF
Operands:
0x01
0
=
=
0x00
1
After Instruction
?
CNT
Z
After Instruction
WDT counter =
WDT prescale =
TO
=
PD
=
=
=
0x00
0
1
1
DECFSZ
Decrement f, Skip if 0
Syntax:
[ label ] DECFSZ f,d
0 ≤ f ≤ 127
d ∈ [0,1]
Operands:
0 ≤ f ≤ 127
d ∈ [0,1]
Operation:
( f ) → (dest)
Operation:
(f) – 1 → (dest); skip if result = 0
Status Affected:
Z
Status Affected:
None
Encoding:
00
1001
f,d
dfff
ffff
Description:
The contents of register 'f' are complemented. If 'd' is 0 the result is stored in
W. If 'd' is 1 the result is stored back in
register 'f'.
Words:
1
Cycles:
1
Example
COMF
REG1,0
Before Instruction
REG1
=
0x13
=
=
0x13
0xEC
After Instruction
REG1
W
Encoding:
Description:
00
dfff
ffff
The contents of register 'f' are decremented. If 'd' is 0 the result is placed in
the W register. If 'd' is 1 the result is
placed back in register 'f'. If the result is
0, the next instruction, which is already
fetched, is discarded. A NOP is executed
instead making it a two cycle instruction.
Words:
1
Cycles:
1(2)
Example
1011
HERE
DECFSZ
GOTO
CONTINUE •
•
•
CNT, 1
LOOP
Before Instruction
PC
=
addressHERE
After Instruction
CNT
if CNT
PC
if CNT
PC
DS30430B-page 60
=
=
=
≠
=
CNT - 1
0,
address CONTINUE
0,
address HERE+1
PIC16F8X
GOTO
Go to address
INCFSZ
Increment f, Skip if 0
Syntax:
[ label ]
Syntax:
[ label ]
Operands:
0 ≤ k ≤ 2047
Operands:
Operation:
k → (PC<10:0>)
(PCLATH<4:3>) → (PC<12:11>)
0 ≤ f ≤ 127
d ∈ [0,1]
Operation:
(f) + 1 → (dest), skip if result = 0
None
Status Affected:
None
Status Affected:
Encoding:
GOTO k
10
1kkk
kkkk
kkkk
Description:
GOTO is an unconditional branch. The
eleven bit immediate value is loaded
into PC bits <10:0>. The upper bits of
PC are loaded from PCLATH<4:3>.
GOTO is a two cycle instruction.
Words:
1
Cycles:
2
Example
GOTO THERE
After Instruction
PC =
Address THERE
Encoding:
Description:
00
INCFSZ f,d
1111
dfff
ffff
The contents of register 'f' are incremented. If 'd' is 0 the result is placed
in the W register. If 'd' is 1 the result is
placed back in register 'f'.
If the result is 0, the next instruction,
which is already fetched, is discarded.
A NOP is executed instead making it
a two cycle instruction.
Words:
1
Cycles:
1(2)
Example
HERE
1
INCFSZ
CNT,
GOTO
CONTINUE •
•
•
LOOP
Before Instruction
PC
=
addressHERE
After Instruction
CNT =
if CNT =
PC
=
if CNT≠
PC
=
CNT + 1
0,
addressCONTINUE
0,
addressHERE +1
INCF
Increment f
IORLW
Inclusive OR Literal with W
Syntax:
[ label ]
Syntax:
[ label ]
Operands:
0 ≤ f ≤ 127
d ∈ [0,1]
Operands:
0 ≤ k ≤ 255
Operation:
(f) + 1 → (dest)
(W) .OR. (k) → (W)
Operation:
Status Affected:
Z
Status Affected:
Z
Encoding:
Description:
Encoding:
00
1010
dfff
ffff
The contents of register 'f' are incremented. If 'd' is 0 the result is placed
in the W register. If 'd' is 1 the result is
Words:
1
Cycles:
1
Example
INCF f,d
kkkk
kkkk
OR’ed to the eight bit literal 'k'. The
result is placed in the W register.
Words:
1
Cycles:
1
IORLW
0x35
Before Instruction
CNT, 1
W
Before Instruction
CNT
Z
1000
Description:
Example
INCF
11
IORLW k
=
0x9A
After Instruction
=
=
0xFF
0
=
=
0x00
1
W
=
0xBF
After Instruction
CNT
Z
DS30430B-page 61
PIC16F8X
IORWF
Inclusive OR W with f
MOVF
Move f
Syntax:
[ label ]
Syntax:
[ label ]
Operands:
0 ≤ f ≤ 127
d ∈ [0,1]
Operands:
0 ≤ f ≤ 127
d ∈ [0,1]
Operation:
(W) .OR. (f) → (W)
Operation:
(f) → (dest)
Status Affected:
Z
Status Affected:
Z
Encoding:
00
IORWF
f,d
0100
dfff
ffff
Description:
Inclusive OR the W register to register
'f'. If 'd' is 0 the result is placed in the
W register. If 'd' is 1 the result is
Words:
1
Cycles:
1
Example
IORWF
RESULT, 0
Before Instruction
RESULT =
W
=
Encoding:
Description:
00
1000
Words:
1
Cycles:
1
MOVF
FSR, 0
W =value in FSR register
RESULT =
W
=
0x13
0x93
MOVLW
Move literal to W
MOVWF
Move W to f
Syntax:
[ label ]
Syntax:
[ label ]
Operands:
0 ≤ k ≤ 255
Operands:
0 ≤ f ≤ 127
Operation:
k → (W)
Operation:
(W) → (f)
Status Affected:
None
Status Affected:
None
11
MOVLW k
00XX
kkkk
kkkk
Description:
The eight bit literal 'k' is loaded into W
register. The don’t cares will assemble as 0’s.
Words:
1
Cycles:
1
Example
Encoding:
0x5A
=
0000
f
1fff
ffff
Move data from W register to register
'f'.
Words:
1
Cycles:
1
MOVWF
OPTION
Before Instruction
After Instruction
W
00
MOVWF
Description:
Example
MOVLW
ffff
After Instruction
After Instruction
Encoding:
dfff
The contents of register f is moved to
destination d. If d = 0, destination is W
register. If d = 1, the destination is file
register f itself. d = 1 is useful to test a
file register since status flag Z is
affected.
Example
0x13
0x91
MOVF f,d
0x5A
OPTION =
W
=
0xFF
0x4F
After Instruction
OPTION =
W
=
DS30430B-page 62
0x4F
0x4F
PIC16F8X
NOP
No Operation
RETFIE
Return from Interrupt
Syntax:
[ label ]
Syntax:
[ label ]
Operands:
None
Operands:
None
Operation:
No operation
Operation:
Status Affected:
None
TOS → (PC),
1 → GIE
Status Affected:
None
Encoding:
00
NOP
0000
0xx0
0000
RETFIE
No operation.
Encoding:
Words:
1
Description:
Cycles:
1
The Stack is popped and Top of Stack
(TOS) is loaded into the PC. Interrupts
are enabled by setting the Global
Interrupt Enable bit. This is a two
cycle instruction.
Words:
1
Cycles:
2
Description:
Example
00
NOP
Example
0000
0000
1001
RETFIE
After Interrupt
PC =
GIE =
TOS
1
OPTION
Load Option Register
RETLW
Return Literal to W
Syntax:
[ label ]
Syntax:
[ label ]
Operands:
None
Operands:
0 ≤ k ≤ 255
Operation:
(W) → OPTION
Operation:
k → (W),
TOS → (PC)
Status Affected:
None
OPTION
Status Affected: None
Encoding:
00
Description:
Words:
Cycles:
0000
0110
0010
loaded in the OPTION register. This
instruction is supported for code compatibility with PIC16C5X products.
Since OPTION is a readable/writable
register, the user can directly address
it.
Description:
11
Words:
1
1
Cycles:
2
Example
future PIC16FXX products, do not use
this instruction.
01xx
kkkk
kkkk
The W register is loaded with the eight
bit literal 'k'. The program counter is
loaded from the top of the stack (the
return address). This is a two cycle
instruction.
1
Example
Note:
Encoding:
RETLW k
CALL TABLE ;W contains table
;offset value
•
;W now has table value
•
•
TABLE ADDWF PC
;W = offset
RETLW k1
;Begin table
RETLW k2
;
•
•
•
RETLW kn
;End of table
Before Instruction
W
=
0x07
After Instruction
W
=
value of k7
DS30430B-page 63
PIC16F8X
RETURN
Return from Subroutine
RRF
Rotate Right f through Carry
Syntax:
[ label ]
Syntax:
[ label ]
Operands:
None
Operands:
Operation:
TOS → (PC)
0 ≤ f ≤ 127
d ∈ [0,1]
Status Affected:
None
Operation:
See description below
Status Affected:
C
Encoding:
Description:
00
0000
0000
1000
Return from subroutine. The stack is
popped and the Top of Stack (TOS) is
loaded into the program counter. This
is a two cycle instruction.
Words:
1
Cycles:
2
Example
RETURN
Encoding:
Description:
RRF f,d
00
1100
C
PC =
TOS
Words:
1
Cycles:
1
Example
ffff
The contents of register 'f' are rotated
one bit to the right through the Carry
Flag. If 'd' is 0 the result is placed in the
W register. If 'd' is 1 the result is placed
RETURN
After Interrupt
dfff
Register f
RRF
REG1,0
Before Instruction
REG1
C
=
=
1110 0110
0
=
=
=
1110 0110
0111 0011
1
After Instruction
REG1
W
C
RLF
Rotate Left f through Carry
SLEEP
Go into Standby Mode
Syntax:
[ label ]
Syntax:
[ label ]
Operands:
0 ≤ f ≤ 127
d ∈ [0,1]
Operands:
None
Operation:
00h → WDT,
0 → WDT prescaler
1 → TO,
0 → PD
Status Affected:
TO, PD
RLF
f,d
Operation:
See description below
Status Affected:
C
Encoding:
Description:
00
1101
ffff
The contents of register 'f' are
rotated one bit to the left through
the Carry Flag. If 'd' is 0 the result
is placed in the W register. If 'd' is
1 the result is stored back in register 'f'.
C
Words:
1
Cycles:
1
Example
dfff
Encoding:
REG1,0
Before Instruction
REG1
C
=
=
1110 0110
0
=
=
=
1110 0110
1100 1100
1
0000
0110
0011
Description:
The power down status bit (PD)
is cleared. Time-out status bit
(TO) is set. Watchdog Timer and
its prescaler are cleared.
The processor is put into SLEEP
mode with the oscillator
stopped.
Words:
1
Cycles:
1
Example:
SLEEP
Register f
RLF
00
SLEEP
After Instruction
REG1
W
C
DS30430B-page 64
PIC16F8X
SUBLW
Subtract W from Literal
SUBWF
Subtract W from f
Syntax:
[ label ]
Syntax:
[ label ]
Operands:
0 ≤ k ≤ 255
Operands:
Operation:
k – (W) → (W)
0 ≤ f ≤ 127
d ∈ [0,1]
Status Affected:
C, DC, Z
Operation:
(f) – (W) → (dest)
Status Affected:
C, DC, Z
Encoding:
Description:
SUBLW k
11
110x
kkkk
kkkk
The W register is subtracted (2’s
complement method) from the
eight bit literal 'k'. The result is
placed in the W register.
Words:
1
Cycles:
1
Example 1:
SUBLW
0x02
Before Instruction
W
C
= 1
= ?
Encoding:
Example 2:
1
Cycles:
1
Example 1:
SUBWF
Example 3:
REG1 = 3
W
= 2
C
= ?
After Instruction
= 2
= ?
REG1 = 1
W
= 2
C
= 1; result is positive
Example 2:
= 3
= ?
After Instruction
After Instruction
W
C
Before Instruction
REG1 = 2
W
= 2
C
= ?
Before Instruction
W
C
REG1,1
Before Instruction
= 1
= 1; result is positive
= 0
= 1; result is zero
ffff
Words:
After Instruction
W
C
dfff
Subtract (2’s complement methodize W register from register 'f'.
If 'd' is 0 the result is stored in
the W register. If 'd' is 1 the
result is stored back in register
'f'.
Before Instruction
W
C
0010
Description:
After Instruction
W
C
00
SUBWF f,d
REG1 = 0
W
= 2
C
= 1; result is zero
= FF
= 0; result is negative
Example 3:
Before Instruction
REG1 = 1
W
= 2
C
= ?
After Instruction
REG1 = FF
W
= 2
C
= 0; result is negative
DS30430B-page 65
PIC16F8X
SWAPF
Swap f
Syntax:
[ label
]
Operands:
0 ≤ f ≤ 127
d ∈ [0,1]
Operation:
(f<3:0>) → (dest<7:4>),
(f<7:4>) → (dest<3:0>)
Status Affected:
00
1
Cycles:
1
Example
Syntax:
[ label ]
Operands:
0 ≤ k ≤ 255
Operation:
(W) .XOR. k → (W)
Status Affected:
Z
Description:
1110
dfff
ffff
The upper and lower nibbles of
register 'f' are exchanged. If 'd' is
0 the result is placed in W register.
If 'd' is 1 the result is placed in register 'f'.
Words:
Exclusive OR Literal with W
Encoding:
None
Encoding:
Description:
SWAPF f,d
XORLW
XORLW k
11
1010
kkkk
kkkk
The contents of the W register
are XOR’ed with the eight bit literal 'k'. The result is placed in
the W register.
Words:
1
Cycles:
1
Example:
XORLW
0xAF
Before Instruction
W
SWAP F REG,
0
0xB5
After Instruction
Before Instruction
REG1
=
W
=
0xA5
=
=
0xA5
0x5A
=
0x1A
After Instruction
REG1
W
TRIS
Load TRIS Register
XORWF
Exclusive OR W with f
Syntax:
[ label ] XORWF
Operands:
0 ≤ f ≤ 127
d ∈ [0,1]
Operation:
(W) .XOR. (f) → (dest)
Status Affected:
Z
Syntax:
[ label ] TRIS
Operands:
5≤f≤7
Operation:
(W) → TRIS register (f)
f
Status Affected: None
Encoding:
00
Description:
0000
0110
0fff
The instruction is supported for code
compatibility with the PIC16C5X products. Since TRIS registers are readable and writable, the user can directly
address them.
Words:
1
Cycles:
1
Example
Note:
future PIC16FXX products, do not use
this instruction.
Encoding:
Description:
00
0110
f,d
dfff
ffff
Exclusive OR the contents of the
W register with register 'f'. If 'd' is
0 the result is stored in the W register. If 'd' is 1 the result is stored
Words:
1
Cycles:
1
Example
XORWF
REG
1
Before Instruction
REG
W
=
=
0xAF
0xB5
=
=
0x1A
0xB5
After Instruction
REG
W
DS30430B-page 66
PIC16F8X
10.0
DEVELOPMENT SUPPORT
10.1
Development Tools
The PIC16/17 microcontrollers are supported with a full
range of hardware and software development tools:
• PICMASTER/PICMASTER CE Real-Time
In-Circuit Emulator
• ICEPIC Low-Cost PIC16C5X and PIC16CXXX
In-Circuit Emulator
• PRO MATE II Universal Programmer
• PICSTART Plus Entry-Level Prototype
Programmer
• PICDEM-1 Low-Cost Demonstration Board
• MPASM Assembler
• MPLAB-SIM Software Simulator
• MPLAB-C (C Compiler)
• Fuzzy logic development system (fuzzyTECH−MP)
10.2
PICMASTER: High Performance
Universal In-Circuit Emulator with
MPLAB IDE
10.3
ICEPIC: Low-cost PIC16CXXX InCircuit Emulator
ICEPIC is a low-cost in-circuit emulator solution for the
Microchip PIC16C5X and PIC16CXXX families of 8-bit
OTP microcontrollers.
ICEPIC is designed to operate on PC-compatible
machines ranging from 286-AT through Pentium
based machines under Windows 3.x environment.
ICEPIC features real time, non-intrusive emulation.
10.4
PRO MATE II: Universal Programmer
The PRO MATE II Universal Programmer is a full-featured programmer capable of operating in stand-alone
mode as well as PC-hosted mode.
The PRO MATE II has programmable VDD and VPP
supplies which allows it to verify programmed memory
at VDD min and VDD max for maximum reliability. It has
an LCD display for displaying error messages, keys to
enter commands and a modular detachable socket
assembly to support various package types. In standalone mode the PRO MATE II can read, verify or program PIC16C5X, PIC16CXXX, PIC17CXX and
PIC14000 devices. It can also set configuration and
code-protect bits in this mode.
The PICMASTER Universal In-Circuit Emulator is
intended to provide the product development engineer
with a complete microcontroller design tool set for all
microcontrollers in the PIC12C5XX, PIC14000,
PIC16C5X, PIC16CXXX and PIC17CXX families.
PICMASTER is supplied with the MPLAB Integrated
Development Environment (IDE), which allows editing,
“make” and download, and source debugging from a
single environment.
10.5
Interchangeable target probes allow the system to be
easily reconfigured for emulation of different processors. The universal architecture of the PICMASTER
allows expansion to support all new Microchip microcontrollers.
PICSTART Plus supports all PIC12C5XX, PIC14000,
PIC16C5X, PIC16CXXX and PIC17CXX devices with
up to 40 pins. Larger pin count devices such as the
PIC16C923 and PIC16C924 may be supported with an
adapter socket.
PICSTART Plus Entry Level
Development System
The PICSTART programmer is an easy-to-use, lowcost prototype programmer. It connects to the PC via
one of the COM (RS-232) ports. MPLAB Integrated
Development Environment software makes using the
programmer simple and efficient. PICSTART Plus is
not recommended for production programming.
The PICMASTER Emulator System has been
designed as a real-time emulation system with
advanced features that are generally found on more
expensive development tools. The PC compatible 386
(and higher) machine platform and Microsoft Windows
3.x environment were chosen to best make these features available to you, the end user.
A CE compliant version of PICMASTER is available for
European Union (EU) countries.
DS30430B-page 67
PIC16F8X
10.6
PICDEM-1 Low-Cost PIC16/17
Demonstration Board
The PICDEM-1 is a simple board which demonstrates
the capabilities of several of Microchip’s microcontrollers. The microcontrollers supported are: PIC16C5X
(PIC16C54 to PIC16C58A), PIC16C61, PIC16C62X,
PIC16C71, PIC16C8X, PIC17C42, PIC17C43 and
PIC17C44. All necessary hardware and software is
included to run basic demo programs. The users can
program the sample microcontrollers provided with
the PICDEM-1 board, on a PRO MATE II or
PICSTART-16B programmer, and easily test firmware. The user can also connect the PICDEM-1
board to the PICMASTER emulator and download
the firmware to the emulator for testing. Additional prototype area is available for the user to build some additional hardware and connect it to the microcontroller
socket(s). Some of the features include an RS-232
interface, a potentiometer for simulated analog input,
push-button switches and eight LEDs connected to
PORTB.
10.7
PICDEM-2 Low-Cost PIC16CXX
Demonstration Board
The PICDEM-2 is a simple demonstration board that
supports the PIC16C62, PIC16C64, PIC16C65,
PIC16C73 and PIC16C74 microcontrollers. All the
necessary hardware and software is included to
run the basic demonstration programs. The user
can program the sample microcontrollers provided
with the PICDEM-2 board, on a PRO MATE II programmer or PICSTART-16C, and easily test firmware.
The PICMASTER emulator may also be used with the
PICDEM-2 board to test firmware. Additional prototype
area has been provided to the user for adding additional hardware and connecting it to the microcontroller
socket(s). Some of the features include a RS-232 interface, push-button switches, a potentiometer for simulated analog input, a Serial EEPROM to demonstrate
usage of the I2C bus and separate headers for connection to an LCD module and a keypad.
10.8
PICDEM-3 Low-Cost PIC16CXXX
Demonstration Board
The PICDEM-3 is a simple demonstration board that
supports the PIC16C923 and PIC16C924 in the PLCC
package. It will also support future 44-pin PLCC
microcontrollers with a LCD Module. All the necessary hardware and software is included to run the
basic demonstration programs. The user can program the sample microcontrollers provided with
the PICDEM-3 board, on a PRO MATE II programmer or PICSTART Plus with an adapter socket, and
easily test firmware. The PICMASTER emulator may
also be used with the PICDEM-3 board to test firmware. Additional prototype area has been provided to
the user for adding hardware and connecting it to the
microcontroller socket(s). Some of the features
DS30430B-page 68
include an RS-232 interface, push-button switches, a
potentiometer for simulated analog input, a thermistor
and separate headers for connection to an external
LCD module and a keypad. Also provided on the
PICDEM-3 board is an LCD panel, with 4 commons
and 12 segments, that is capable of displaying time,
temperature and day of the week. The PICDEM-3 provides an additional RS-232 interface and Windows 3.1
software for showing the demultiplexed LCD signals on
a PC. A simple serial interface allows the user to construct a hardware demultiplexer for the LCD signals.
PICDEM-3 will be available in the 3rd quarter of 1996.
10.9
MPLAB Integrated Development
Environment Software
The MPLAB IDE Software brings an ease of software
development previously unseen in the 8-bit microcontroller market. MPLAB is a windows based application
which contains:
• A full featured editor
• Three operating modes
- editor
- emulator
- simulator
• A project manager
• Customizable tool bar and key mapping
• A status bar with project information
• Extensive on-line help
MPLAB allows you to:
• Edit your source files (either assembly or ‘C’)
• One touch assemble (or compile) and download
to PIC16/17 tools (automatically updates all
project information)
• Debug using:
- source files
- absolute listing file
• Transfer data dynamically via DDE (soon to be
replaced by OLE)
• Run up to four emulators on the same PC
The ability to use MPLAB with Microchip’s simulator
allows a consistent platform and the ability to easily
switch from the low cost simulator to the full featured
emulator with minimal retraining due to development
tools.
10.10
Assembler (MPASM)
The MPASM Universal Macro Assembler is a PChosted symbolic assembler. It supports all microcontroller series including the PIC12C5XX, PIC14000,
PIC16C5X, PIC16CXXX, and PIC17CXX families.
MPASM offers full featured Macro capabilities, conditional assembly, and several source and listing formats.
It generates various object code formats to support
Microchip's development tools as well as third party
programmers.
PIC16F8X
MPASM allow full symbolic debugging from the
Microchip
Universal
Emulator
System
(PICMASTER).
Both versions include Microchip’s fuzzyLAB demonstration board for hands-on experience with fuzzy logic
systems implementation.
MPASM has the following features to assist in developing software for specific use applications.
10.14
• Provides translation of Assembler source code to
object code for all Microchip microcontrollers.
• Macro assembly capability.
• Produces all the files (Object, Listing, Symbol,
and special) required for symbolic debug with
Microchip’s emulator systems.
• Supports Hex (default), Decimal and Octal
source and listing formats.
MPASM provides a rich directive language to support
programming of the PIC16/17. Directives are helpful in
making the development of your assemble source
code shorter and more maintainable.
10.11
MPLAB-SIM fully supports symbolic debugging using
MPLAB-C and MPASM. The Software Simulator offers
the low cost flexibility to develop and debug code outside of the laboratory environment making it an excellent multi-project software development tool.
C Compiler (MPLAB-C)
The MPLAB-C Code Development System is a
complete ‘C’ compiler and integrated development
environment for Microchip’s PIC16/17 family of microcontrollers. The compiler provides powerful integration
capabilities and ease of use not found with other
compilers.
For easier source level debugging, the compiler provides symbol information that is compatible with the
MPLAB IDE memory display (PICMASTER emulator
software versions 1.13 and later).
10.13
MP-DriveWay is an easy-to-use Windows-based Application Code Generator. With MP-DriveWay you can
visually configure all the peripherals in a PIC16/17
device and, with a click of the mouse, generate all the
initialization and many functional code modules in C
language. The output is fully compatible with Microchip’s MPLAB-C C compiler. The code produced is
highly modular and allows easy integration of your own
code. MP-DriveWay is intelligent enough to maintain
your code through subsequent code generation.
10.15
SEEVAL Evaluation and
Programming System
Software Simulator (MPLAB-SIM)
The MPLAB-SIM Software Simulator allows code
development in a PC host environment. It allows the
user to simulate the PIC16/17 series microcontrollers
on an instruction level. On any given instruction, the
user may examine or modify any of the data areas or
provide external stimulus to any of the pins. The input/
output radix can be set by the user and the execution
can be performed in; single step, execute until break,
or in a trace mode.
10.12
MP-DriveWay – Application Code
Generator
The SEEVAL SEEPROM Designer’s Kit supports all
Microchip 2-wire and 3-wire Serial EEPROMs. The kit
includes everything necessary to read, write, erase or
program special features of any Microchip SEEPROM
product including Smart Serials and secure serials.
The Total Endurance Disk is included to aid in tradeoff analysis and reliability calculations. The total kit can
significantly reduce time-to-market and result in an
optimized system.
10.16
TrueGauge Intelligent Battery
Management
The TrueGauge development tool supports system
development with the MTA11200B TrueGauge Intelligent Battery Management IC. System design verification can be accomplished before hardware prototypes
are built. User interface is graphically-oriented and
measured data can be saved in a file for exporting to
Microsoft Excel.
10.17
KEELOQ Evaluation and
Programming Tools
KEELOQ evaluation and programming tools support
Microchips HCS Secure Data Products. The HCS evaluation kit includes an LCD display to show changing
codes, a decoder to decode transmissions, and a programming interface to program test transmitters.
Fuzzy Logic Development System
(fuzzyTECH-MP)
fuzzyTECH-MP fuzzy logic development tool is available in two versions - a low cost introductory version,
MP Explorer, for designers to gain a comprehensive
working knowledge of fuzzy logic system design; and a
full-featured version, fuzzyTECH-MP, edition for implementing more complex systems.
DS30430B-page 69
DS30430B-page 70
SW006005
SW006005
SW006005
SW007002
SW007002
SW007002
SW007002
PIC16C61
PIC16C62, 62A,
64, 64A
PIC16C620, 621, 622
SW006005
SW007002
SW007002
SW007002
SW007002
SW007002
SW007002
SW007002
SW007002
PIC16C71
PIC16C710, 711
PIC16C72
PIC16F83
PIC16C84
PIC16F84
PIC16C923, 924*
SW006006
SW006006
SW006006
SW006006
SW006006
SW006006
SW006006
—
SW006006
DV005001/
DV005002
DV005001/
DV005002
DV005001/
DV005002
DV005001/
DV005002
DV005001/
DV005002
DV005001/
DV005002
DV005001/
DV005002
—
DV005001/
DV005002
DV005001/
DV005002
DV005001/
DV005002
DV005001/
DV005002
DV005001/
DV005002
DV005001/
DV005002
—
—
fuzzyTECH-MP
Explorer/Edition
Fuzzy Logic
Dev. Tool
—
Product
All 2 wire and 3 wire
Serial EEPROM's
MTA11200B
HCS200, 300, 301 *
SEEVAL Designers Kit
DV243001
N/A
N/A
TRUEGAUGE Development Kit
N/A
DV114001
N/A
PIC17C42,
SW007002
SW006005
SW006006
42A, 43, 44
*Contact Microchip Technology for availability date
**MPLAB Integrated Development Environment includes MPLAB-SIM Simulator and
MPASM Assembler
SW006005
SW006005
SW006005
SW006005
SW006005
SW006005
SW006005
SW006005
SW007002
PIC16C63, 65, 65A,
73, 73A, 74, 74A
PIC16C642, 662*
SW006006
SW006006
SW006006
—
SW006006
—
MP-DriveWay
Applications
Code
Generator
—
N/A
PG306001
Hopping Code Security Programmer Kit
N/A
N/A
DM303001
Hopping Code Security Eval/Demo Kit
N/A
****PRO MATE PICSTART Lite PICSTART Plus
*** PICMASTER/
ICEPIC
Low-Cost
PICMASTER-CE
Ultra Low-Cost
Low-Cost
II Universal
In-Circuit
In-Circuit
Dev. Kit
Universal
Microchip
Emulator
Emulator
Dev. Kit
Programmer
EM167015/
—
DV007003
—
DV003001
EM167101
EM147001/
—
DV007003
—
DV003001
EM147101
EM167015/
EM167201
DV007003
DV162003
DV003001
EM167101
EM167033/
—DV007003
—
DV003001
EM167113
EM167021/
EM167205
DV007003
DV162003
DV003001
N/A
EM167025/
EM167203
DV007003
DV162002
DV003001
EM167103
EM167023/
EM167202
DV007003
DV162003
DV003001
EM167109
EM167025/
EM167204
DV007003
DV162002
DV003001
EM167103
EM167035/
—DV007003
DV162002
DV003001
EM167105
EM167027/
EM167205
DV007003
DV162003
DV003001
EM167105
EM167027/
—
DV007003
DV162003
DV003001
EM167105
EM167025/
—
DV007003
DV162002
DV003001
EM167103
EM167029/
—
DV007003
DV162003
DV003001
EM167107
EM167029/
EM167206
DV007003
DV162003
DV003001
EM167107
EM167029/
—
DV007003
DV162003
DV003001
EM167107
EM167031/
—
DV007003
—
DV003001
EM167111
EM177007/
—
DV007003
—
DV003001
EM177107
***All PICMASTER and PICMASTER-CE ordering part numbers above include
PRO MATE II programmer
****PRO MATE socket modules are ordered separately. See development systems
ordering guide for specific ordering part numbers
TABLE 10-1:
SW006005
SW006005
SW007002
PIC16C52, 54, 54A,
55, 56, 57, 58A
PIC16C554, 556, 558
SW006005
SW006005
MPLAB C
Compiler
SW007002
** MPLAB
Integrated
Development
Environment
SW007002
PIC14000
PIC12C508, 509
Product
PIC16F8X
DEVELOPMENT TOOLS FROM MICROCHIP
PIC16F8X
Applicable Devices F83 CR83 F84 CR84
11.0
ELECTRICAL CHARACTERISTICS FOR PIC16F83 AND PIC16F84
Absolute Maximum Ratings †
Ambient temperature under bias.............................................................................................................-55°C to +125°C
Storage temperature .............................................................................................................................. -65°C to +150°C
Voltage on VDD with respect to VSS .......................................................................................................... -0.3 to +7.5V
Voltage on MCLR with respect to VSS(2) ...................................................................................................... -0.3 to +14V
Voltage on any pin with respect to VSS (except VDD and MCLR) ................................................... -0.6V to (VDD + 0.6V)
Total power dissipation(1) .....................................................................................................................................800 mW
Maximum current out of VSS pin ...........................................................................................................................150 mA
Maximum current into VDD pin ..............................................................................................................................100 mA
Input clamp current, IIK (VI < 0 or VI > VDD) .....................................................................................................................± 20 mA
Output clamp current, IOK (VO < 0 or VO > VDD) .............................................................................................................± 20 mA
Maximum output current sunk by any I/O pin..........................................................................................................25 mA
Maximum output current sourced by any I/O pin ....................................................................................................20 mA
Maximum current sunk by PORTA ..........................................................................................................................80 mA
Maximum current sourced by PORTA.....................................................................................................................50 mA
Maximum current sunk by PORTB........................................................................................................................150 mA
Maximum current sourced by PORTB ..................................................................................................................100 mA
Note 1: Power dissipation is calculated as follows: Pdis = VDD x {IDD - ∑ IOH} + ∑ {(VDD-VOH) x IOH} + ∑(VOl x IOL)
Note 2: Voltage spikes below VSS at the MCLR pin, inducing currents greater than 80 mA, may cause latch-up.
Thus, a series resistor of 50-100Ω should be used when applying a “low” level to the MCLR pin rather than
pulling this pin directly to VSS.
† NOTICE: Stresses above those listed under “Absolute Maximum Ratings” may cause permanent damage to the
device. This is a stress rating only and functional operation of the device at those or any other conditions above
those indicated in the operation listings of this specification is not implied. Exposure to maximum rating conditions for
extended periods may affect device reliability.
DS30430B-page 71
PIC16F8X
TABLE 11-1:
CROSS REFERENCE OF DEVICE SPECS FOR OSCILLATOR CONFIGURATIONS
AND FREQUENCIES OF OPERATION (COMMERCIAL DEVICES)
PIC16F84-04
PIC16F83-04
OSC
RC
XT
HS
LP
PIC16F84-10
PIC16F83-10
VDD:
IDD:
IPD:
Freq:
VDD:
IDD:
IPD:
Freq:
VDD:
IDD:
IPD:
Freq:
VDD:
IDD:
IPD:
Freq:
VDD:
IDD:
IPD:
Freq:
VDD:
IDD:
IPD:
Freq:
4.0V to 6.0V
4.5 mA max. at 5.5V
14 µA max. at 4V WDT dis
4.0 MHz max.
4.0V to 6.0V
4.5 mA max. at 5.5V
4.0 MHz max.
4.5V to 5.5V
4.5 mA typ. at 5.5V
1.0 µA typ. at 4.5V WDT dis
4.0 MHz max.
4.5V to 5.5V
1.8 mA typ. at 5.5V
4..0 MHz max.
4.5V to 5.5V
1.8 mA typ. at 5.5V
4.0 MHz max.
4.5V to 5.5V
10 mA max. at 5.5V typ.
10 MHz max.
VDD:
IDD:
IPD:
Freq:
4.0V to 6.0V
35 µA typ. at 32 kHz, 3.0V
Do not use in LP mode
200 kHz max.
PIC16LF84-04
PIC16LF83-04
VDD:
IDD:
IPD:
Freq:
VDD:
IDD:
IPD:
Freq:
2.0V to 6.0V
4.5 mA max. at 5.5V
7.0 µA max. at 2V WDT dis
2.0 MHz max.
2.0V to 6.0V
4.5 mA max. at 5.5V
2.0 MHz max.
Do not use in HS mode
VDD:
IDD:
IPD:
Freq:
2.0V to 6.0V
32 µA max. at 32 kHz, 3.0V
7 µA max. at 2.0V WDT dis
200 kHz max.
The shaded sections indicate oscillator selections which are tested for functionality, but not for MIN/MAX
specifications. It is recommended that the user select the device type that ensures the specifications
required.
DS30430B-page 72
PIC16F8X
11.1
DC CHARACTERISTICS:
DC Characteristics
Power Supply Pins
Parameter
No.
Sym
Characteristic
D001
D001A
D002
VDD
Supply Voltage
VDR
D003
VPOR
D004
SVDD
RAM Data Retention
Voltage(1)
VDD start voltage to
ensure internal
Power-on Reset signal
VDD rise rate to ensure
internal Power-on
Reset signal
Supply Current(2)
IDD
D010
D010A
PIC16F84, PIC16F83 (Commercial, Industrial)
Standard Operating Conditions (unless otherwise stated)
Operating temperature 0°C ≤ TA ≤ +70°C (commercial)
-40°C ≤ TA ≤ +85°C (industrial)
Min Typ† Max Units
Conditions
4.0
4.5
1.5 *
—
—
6.0
5.5
—
—
0.05*
—
—
—
V
V
V
XT, RC and LP osc configuration
HS osc configuration
Device in SLEEP mode
VSS
—
V
See section on Power-on Reset for details
—
—
1.8
7.3
4.5
10
V/ms See section on Power-on Reset for details
mA
mA
RC and XT osc configuration(4)
FOSC = 4.0 MHz, VDD = 5.5V
(During Flash programming)
HS OSC CONFIGURATION (PIC16F84-10)
FOSC = 10 MHz, VDD = 5.5V
VDD = 4.0V, WDT enabled, industrial
VDD = 4.0V, WDT disabled, commercial
VDD = 4.0V, WDT disabled, industrial
—
D013
5
10
mA
(3)
—
D020
IPD
Power-down Current
7.0
28
µA
—
D021
1.0
14
µA
—
D021A
1.0
16
µA
* These parameters are characterized but not tested.
† Data in "Typ" column is at 5.0V, 25˚C unless otherwise stated. These parameters are for design guidance only
and are not tested.
Note 1: This is the limit to which VDD can be lowered in SLEEP mode without losing RAM data.
2: The supply current is mainly a function of the operating voltage and frequency. Other factors such as I/O pin
loading and switching rate, oscillator type, internal code execution pattern, and temperature also have an
impact on the current consumption.
The test conditions for all IDD measurements in active operation mode are:
OSC1=external square wave, from rail to rail; all I/O pins tristated, pulled to VDD, T0CKI = VDD,
MCLR = VDD; WDT enabled/disabled as specified.
3: The power down current in SLEEP mode does not depend on the oscillator type. Power-down current is
measured with the part in SLEEP mode, with all I/O pins in hi-impedance state and tied to VDD and VSS.
4: For RC osc configuration, current through Rext is not included. The current through the resistor can be estimated by the formula IR = VDD/2Rext (mA) with Rext in kOhm.
DS30430B-page 73
PIC16F8X
11.2
DC CHARACTERISTICS:
PIC16LF84, PIC16LF83 (Commercial, Industrial)
DC Characteristics
Power Supply Pins
Parameter
No.
Sym
Characteristic
2.0
1.5 *
—
—
6.0
—
V
V
XT, RC, and LP osc configuration
—
VSS
—
V
0.05*
—
—
D010
D010A
—
—
1
7.3
4
10
mA
mA
D014
—
15
32
µA
D001
D002
VDD
VDR
D003
VPOR
D004
SVDD
IDD
Supply Voltage
RAM Data Retention
Voltage(1)
ensure internal
Power-on Reset signal
internal Power-on
Reset signal
Supply Current(2)
Conditions
(During Flash programming)
LP osc configuration
FOSC = 32 kHz, VDD = 2.0V,
WDT disabled
IPD
D020
Power-down Current(3)
—
3.0
16
µA
D021
—
0.4
7.0
µA
D021A
—
0.4
9.0
µA
† Data in "Typ" column is at 5.0V, 25°C unless otherwise stated. These parameters are for design guidance only
and are not tested.
4: For RC osc configuration, current through Rext is not included. The current through the resistor can be
estimated by the formula IR = VDD/2Rext (mA) with Rext in kOhm.
DS30430B-page 74
PIC16F8X
11.3
DC CHARACTERISTICS:
PIC16LF84, PIC16LF83 (Commercial, Industrial)
Operating voltage VDD range as described in DC spec
Section 11.1 and Section 11.2.
DC Characteristics
All Pins Except
Power Supply Pins
Parameter
No.
Sym
VIL
D030
D030A
D031
D032
D033
D034
VIH
D040
D040A
D041
D042
D043
D050
VHYS
D070
IPURB
D060
IIL
D061
D063
Characteristic
Input Low Voltage
I/O ports
with TTL buffer
with Schmitt Trigger buffer
MCLR, RA4/T0CKI
OSC1 (XT, HS and LP modes)(1)
OSC1 (RC mode)
Input High Voltage
I/O ports
with TTL buffer
Min
Typ†
Max
Units
VSS
VSS
VSS
Vss
Vss
Vss
—
—
—
—
—
—
0.8
0.16VDD
0.2VDD
0.2VDD
0.3VDD
0.1VDD
V
V
V
V
V
V
4.5 V ≤ VDD ≤ 5.5 V
entire range(4)
entire range
VDD
VDD
VDD
VDD
V
V
4.5 V ≤ VDD ≤ 5.5V
entire range(4)
entire range
—
—
VDD
V
V
250*
400*
—
±1
—
—
±5
±5
2.4
0.48VDD
0.45VDD
0.85 VDD
MCLR, RA4/T0CKI, OSC1
(RC mode)
OSC1 (XT, HS and LP modes)(1) 0.7 VDD
Hysteresis of
TBD
Schmitt Trigger inputs
PORTB weak pull-up current
50*
Input Leakage Current(2,3)
—
I/O ports
MCLR, RA4/T0CKI
OSC1
—
—
—
—
—
—
—
—
Conditions
V
µA VDD = 5.0V, VPIN = VSS
µA Vss ≤ VPIN ≤ VDD,
Pin at hi-impedance
µA Vss ≤ VPIN ≤ VDD
µA Vss ≤ VPIN ≤ VDD, XT, HS and
Output Low Voltage
—
—
I/O ports
0.6
V IOL = 8.5 mA, VDD = 4.5V
—
—
OSC2/CLKOUT
0.6
V IOL = 1.6 mA, VDD = 4.5V
Output High Voltage
—
—
D090
VOH
I/O ports(3)
VDD-0.7
V IOH = -3.0 mA, VDD = 4.5V
—
—
D092
OSC2/CLKOUT
VDD-0.7
V IOH = -1.3 mA, VDD = 4.5V
† Data in “Typ” column is at 5.0V, 25°C unless otherwise stated. These parameters are for design guidance only
and are not tested.
Note 1: In RC oscillator configuration, the OSC1 pin is a Schmitt Trigger input. Do not drive the PIC16F8X with an
external clock while the device is in RC mode, otherwise chip damage may result.
2: The leakage current on the MCLR pin is strongly dependent on the applied voltage level. The specified levels represent normal operating conditions. Higher leakage current may be measured at different input voltages.
3: Negative current is defined as coming out of the pin.
4: The user may use better of the two specs.
D080
D083
VOL
DS30430B-page 75
PIC16F8X
11.4
DC CHARACTERISTICS:
PIC16LF84, PIC16F83 (Commercial, Industrial)
DC Characteristics
All Pins Except
Power Supply Pins
Parameter
No.
Sym
D100
COSC2
D101
CIO
D120
D121
ED
VDRW
D122
TDEW
D130
D131
EP
VPR
Characteristic
Capacitive Loading Specs
on Output Pins
OSC2 pin
All I/O pins and OSC2
(RC mode)
Data EEPROM Memory
Endurance
VDD for read/write
Erase/Write cycle time
Program Flash Memory
Endurance
VDD for read
Operating voltage VDD range as described in DC spec Section 11.1
and Section 11.2.
Min
Typ†
Max Units
Conditions
—
—
15
pF
—
—
50
pF
1M
VMIN
10M
—
6.0
—
—
10
100
VMIN
1000
—
—
6.0
—
In XT, HS and LP modes when
external clock is used to drive
OSC1.
E/W 25°C at 5V
V VMIN = Minimum operating
voltage
ms
E/W
voltage
—
D132
VPEW VDD for erase/write
4.5
5.5
V
—
—
D133
TPEW Erase/Write cycle time
10
ms
and are not tested.
DS30430B-page 76
PIC16F8X
TABLE 11-2:
TIMING PARAMETER SYMBOLOGY
The timing parameter symbols have been created following one of the following formats:
1. TppS2ppS
2. TppS
T
F
Frequency
Lowercase symbols (pp) and their meanings:
pp
2
to
ck
CLKOUT
cy
cycle time
io
I/O port
inp
INT pin
mc
MCLR
Uppercase symbols and their meanings:
S
F
Fall
H
High
I
Invalid (Hi-impedance)
L
Low
T
Time
os,osc
ost
pwrt
rbt
t0
wdt
OSC1
oscillator start-up timer
power-up timer
RBx pins
T0CKI
watchdog timer
P
R
V
Z
Period
Rise
Valid
High Impedance
FIGURE 11-1: PARAMETER MEASUREMENT INFORMATION
All timings are measure between high and low measurement points as indicated in the figures below.
0.7 VDD XTAL
0.8 VDD RC (High)
0.9 VDD (High)
0.3 VDD XTAL
0.15 VDD RC (Low)
OSC1 Measurement Points
0.1 VDD (Low)
I/O Port Measurement Points
FIGURE 11-2: LOAD CONDITIONS
Load Condition 1
Load Condition 2
VDD/2
RL
CL
Pin
CL
Pin
VSS
VSS
RL =
464Ω
CL =
50 pF
for all pins except OSC2.
15 pF
for OSC2 output.
DS30430B-page 77
PIC16F8X
11.5
Timing Diagrams and Specifications
FIGURE 11-3: EXTERNAL CLOCK TIMING
Q4
Q1
Q3
Q2
Q4
Q1
OSC1
1
3
3
4
4
2
CLKOUT
TABLE 11-3:
Parameter
No.
1
EXTERNAL CLOCK TIMING REQUIREMENTS
Sym
Characteristic
Min
Typ†
Max
Units Conditions
FOSC
External CLKIN Frequency(1)
DC
DC
DC
DC
—
—
—
—
2
4
10
200
MHz
MHz
MHz
kHz
XT, RC osc
XT, RC osc
HS osc
LP osc
PIC16LF8X-04
PIC16F8X-04
PIC16F8X-10
PIC16LF8X-04
Oscillator Frequency(1)
DC
DC
0.1
0.1
1.0
DC
—
—
—
—
—
—
2
4
2
4
10
200
MHz
MHz
MHz
MHz
MHz
kHz
RC osc
RC osc
XT osc
XT osc
HS osc
LP osc
PIC16LF8X-04
PIC16F8X-04
PIC16LF8X-04
PIC16F8X-04
PIC16F8X-10
PIC16LF8X-04
External CLKIN Period(1)
500
250
100
5.0
—
—
—
—
—
—
—
—
ns
ns
ns
µs
XT, RC osc
XT, RC osc
HS osc
LP osc
PIC16LF8X-04
PIC16F8X-04
PIC16F8X-10
PIC16LF8X-04
Oscillator Period(1)
500
250
500
250
100
5.0
—
—
—
—
—
—
—
—
10,000
10,000
1,000
—
ns
ns
ns
ns
ns
µs
RC osc
RC osc
XT osc
XT osc
HS osc
LP osc
PIC16LF8X-04
PIC16F8X-04
PIC16LF8X-04
PIC16F8X-04
PIC16F8X-10
PIC16LF8X-04
0.4
60 *
50 *
2.0 *
35 *
25 *
50 *
15 *
4/Fosc
—
—
—
—
—
—
—
DC
—
—
—
—
—
—
—
µs
ns
ns
µs
ns
ns
ns
ns
XT osc
XT osc
LP osc
HS osc
XT osc
LP osc
HS osc
PIC16LF8X-04
PIC16F8X-04
PIC16LF8X-04
PIC16F8X-10
PIC16F8X-04
PIC16LF8X-04
PIC16F8X-10
Tosc
2
3
TCY
TosL,
TosH
Instruction Cycle Time(1)
Clock in (OSC1) High or Low
Time
4
TosR,
TosF
Clock in (OSC1) Rise or Fall Time
* These parameters are characterized but no tested.
and are not tested.
Note 1: Instruction cycle period (TCY) equals four times the input oscillator time-base period. All specified values are
based on characterization data for that particular oscillator type under standard operating conditions with the
device executing code. Exceeding these specified limits may result in an unstable oscillator operation and/or
higher than expected current consumption. All devices are tested to operate at "min." values with an
external clock applied to the OSC1 pin.
When an external clock input is used, the "Max." cycle time limit is "DC" (no clock) for all devices.
DS30430B-page 78
PIC16F8X
FIGURE 11-4: CLKOUT AND I/O TIMING
Q1
Q4
Q2
Q3
OSC1
11
10
22
23
CLKOUT
13
19
14
12
18
16
I/O Pin
(input)
15
17
I/O Pin
(output)
new value
old value
20, 21
Note: All tests must be done with specified capacitive loads (Figure 11-2) 50 pF on I/O pins and CLKOUT.
TABLE 11-4:
Parameter
No.
10
CLKOUT AND I/O TIMING REQUIREMENTS
Sym
Characteristic
TosH2ckL
OSC1↑ to CLKOUT↓
10A
11
TosH2ckH
OSC1↑ to CLKOUT↑
11A
12
TckR
CLKOUT rise time
12A
13
TckF
CLKOUT fall time
13A
Min
Typ†
Max
Units Conditions
PIC16F8X
—
15
30 *
ns
Note 1
PIC16LF8X
—
15
120 *
ns
Note 1
PIC16F8X
—
15
30 *
ns
Note 1
PIC16LF8X
—
15
120 *
ns
Note 1
PIC16F8X
—
15
30 *
ns
Note 1
PIC16LF8X
—
15
100 *
ns
Note 1
PIC16F8X
—
15
30 *
ns
Note 1
PIC16LF8X
—
15
100 *
ns
Note 1
14
TckL2ioV
CLKOUT ↓ to Port out valid
—
—
0.5TCY +20 *
ns
Note 1
15
TioV2ckH
Port in valid before
PIC16F8X
0.30TCY + 30 *
—
—
ns
Note 1
CLKOUT ↑
PIC16LF8X
0.30TCY + 80 *
—
—
ns
Note 1
16
TckH2ioI
Port in hold after CLKOUT ↑
0*
—
—
ns
Note 1
17
TosH2ioV
OSC1↑ (Q1 cycle) to
PIC16F8X
—
—
125 *
ns
Port out valid
PIC16LF8X
—
—
250 *
ns
18
TosH2ioI
OSC1↑ (Q2 cycle) to Port input invalid
(I/O in hold time)
TBD
—
—
ns
19
TioV2osH
Port input valid to OSC1↑
(I/O in setup time)
TBD
—
—
ns
20
TioR
Port output rise time
20A
21
TioF
Port output fall time
21A
22
Tinp
22A
23
23A
Trbp
PIC16F8X
—
10
25 *
ns
PIC16LF8X
—
10
60 *
ns
PIC16F8X
—
10
25 *
ns
PIC16LF8X
—
10
60 *
ns
INT pin high
PIC16F8X
20 *
—
—
ns
or low time
PIC16LF8X
55 *
—
—
ns
RB7:RB4 change INT
PIC16F8X
TOSC §
—
—
ns
high or low time
PIC16LF8X
TOSC §
—
—
ns
and are not tested.
§ By design
Note 1: Measurements are taken in RC Mode where CLKOUT output is 4 x TOSC.
DS30430B-page 79
PIC16F8X
FIGURE 11-5: RESET, WATCHDOG TIMER, OSCILLATOR START-UP TIMER AND POWER-UP
TIMER TIMING
VDD
MCLR
30
Internal
POR
33
PWRT
Time-out
32
OSC
Time-out
Internal
RESET
Watchdog
Timer
RESET
31
34
34
I/O Pins
TABLE 11-5:
RESET, WATCHDOG TIMER, OSCILLATOR START-UP TIMER AND POWER-UP
TIMER REQUIREMENTS
Parameter
No.
Sym
Characteristic
30
TmcL
MCLR Pulse Width (low)
31
Twdt
Watchdog Timer Time-out Period
(No Prescaler)
32
Tost
Oscillation Start-up Timer Period
33
Tpwrt
34
TIOZ
*
†
Power-up Timer Period
I/O Hi-impedance from MCLR Low
or reset
Min
Typ†
Max
Units
1000 *
—
—
ns
2.0V ≤ VDD ≤ 6.0V
7*
18
33 *
ms
VDD = 5.0V
ms
TOSC = OSC1 period
VDD = 5.0V
1024TOSC
28 *
72
132 *
ms
—
—
100 *
ns
Conditions
These parameters are characterized but not tested.
Data in "Typ" column is at 5V, 25°C unless otherwise stated. These parameters are for design guidance only and are not
tested.
DS30430B-page 80
PIC16F8X
FIGURE 11-6: TIMER0 CLOCK TIMINGS
RA4/T0CKI
40
41
42
TABLE 11-6:
Parameter
No.
40
TIMER0 CLOCK REQUIREMENTS
Sym Characteristic
Tt0H T0CKI High Pulse Width
Min
No Prescaler
With Prescaler
41
Tt0L T0CKI Low Pulse Width
No Prescaler
With Prescaler
42
*
†
Tt0P T0CKI Period
Typ† Max Units Conditions
0.5TCY + 20 *
—
—
ns
50 *
30 *
—
—
—
—
ns
ns
0.5TCY + 20 *
—
—
ns
50 *
20 *
—
—
—
—
ns
ns
2.0V ≤ VDD ≤ 3.0V
3.0V ≤ VDD ≤ 6.0V
TCY + 40 *
N
—
—
ns
N = prescale value
(2, 4, ..., 256)
2.0V ≤ VDD ≤ 3.0V
3.0V ≤ VDD ≤ 6.0V
Data in "Typ" column is at 5.0V, 25°C unless otherwise stated. These parameters are for design guidance only and are not
tested.
DS30430B-page 81
PIC16F8X
NOTES:
DS30430B-page 82
PIC16F8X
12.0
DC & AC CHARACTERISTICS GRAPHS/TABLES FOR PIC16F83 AND
PIC16F84
NOT AVAILABLE AT THIS TIME.
DS30430B-page 83
PIC16F8X
NOTES:
DS30430B-page 84
PIC16F8X
13.0
ELECTRICAL CHARACTERISTICS FOR PIC16CR83 AND PIC16CR84
Absolute Maximum Ratings †
Ambient temperature under bias.............................................................................................................-55°C to +125°C
Storage temperature .............................................................................................................................. -65°C to +150°C
Voltage on VDD with respect to VSS .......................................................................................................... -0.3 to +7.5V
Voltage on MCLR with respect to VSS(2) ...................................................................................................... -0.3 to +14V
Voltage on any pin with respect to VSS (except VDD and MCLR) ................................................... -0.6V to (VDD + 0.6V)
Total power dissipation(1) .....................................................................................................................................800 mW
Maximum current out of VSS pin ...........................................................................................................................150 mA
Maximum current into VDD pin ..............................................................................................................................100 mA
Input clamp current, IIK (VI < 0 or VI > VDD) .....................................................................................................................± 20 mA
Output clamp current, IOK (VO < 0 or VO > VDD) .............................................................................................................± 20 mA
Maximum output current sunk by any I/O pin..........................................................................................................25 mA
Maximum output current sourced by any I/O pin ....................................................................................................20 mA
Maximum current sunk by PORTA ..........................................................................................................................80 mA
Maximum current sourced by PORTA.....................................................................................................................50 mA
Maximum current sunk by PORTB........................................................................................................................150 mA
Maximum current sourced by PORTB ..................................................................................................................100 mA
Note 1: Power dissipation is calculated as follows: Pdis = VDD x {IDD - ∑ IOH} + ∑ {(VDD-VOH) x IOH} + ∑(VOl x IOL)
Note 2: Voltage spikes below VSS at the MCLR pin, inducing currents greater than 80 mA, may cause latch-up.
Thus, a series resistor of 50-100Ω should be used when applying a “low” level to the MCLR pin rather than
pulling this pin directly to VSS.
† NOTICE: Stresses above those listed under “Absolute Maximum Ratings” may cause permanent damage to the
device. This is a stress rating only and functional operation of the device at those or any other conditions above
those indicated in the operation listings of this specification is not implied. Exposure to maximum rating conditions for
extended periods may affect device reliability.
DS30430B-page 85
PIC16F8X
TABLE 13-1:
CROSS REFERENCE OF DEVICE SPECS FOR OSCILLATOR CONFIGURATIONS
AND FREQUENCIES OF OPERATION (COMMERCIAL DEVICES)
PIC16CR84-04
PIC16CR83-04
OSC
RC
XT
HS
LP
PIC16CR84-10
PIC16CR83-10
VDD:
IDD:
IPD:
Freq:
VDD:
IDD:
IPD:
Freq:
VDD:
IDD:
IPD:
Freq:
VDD:
IDD:
IPD:
Freq:
VDD:
IDD:
IPD:
Freq:
VDD:
IDD:
IPD:
Freq:
4.0V to 6.0V
4.5 mA max. at 5.5V
4.0 MHz max.
4.0V to 6.0V
4.5 mA max. at 5.5V
4.0 MHz max.
4.5V to 5.5V
4.5 mA typ. at 5.5V
4.0 MHz max.
4.5V to 5.5V
1.8 mA typ. at 5.5V
4..0 MHz max.
4.5V to 5.5V
1.8 mA typ. at 5.5V
4.0 MHz max.
4.5V to 5.5V
10 mA max. at 5.5V typ.
10 MHz max.
VDD:
IDD:
IPD:
Freq:
4.0V to 6.0V
35 µA typ. at 32 kHz, 3.0V
Do not use in LP mode
200 kHz max.
PIC16LCR84-04
PIC16LCR83-04
VDD:
IDD:
IPD:
Freq:
VDD:
IDD:
IPD:
Freq:
2.0V to 6.0V
4.5 mA max. at 5.5V
2.0 MHz max.
2.0V to 6.0V
4.5 mA max. at 5.5V
2.0 MHz max.
Do not use in HS mode
VDD:
IDD:
IPD:
Freq:
2.0V to 6.0V
32 µA max. at 32 kHz, 3.0V
200 kHz max.
The shaded sections indicate oscillator selections which are tested for functionality, but not for MIN/MAX
specifications. It is recommended that the user select the device type that ensures the specifications
required.
DS30430B-page 86
PIC16F8X
13.1
DC CHARACTERISTICS:
DC Characteristics
Power Supply Pins
Parameter
No.
Sym
Characteristic
D001
D001A
D002
VDD
Supply Voltage
VDR
D003
VPOR
D004
SVDD
RAM Data Retention
Voltage(1)
ensure internal Poweron Reset signal
internal Power-on
Reset signal
Supply Current(2)
IDD
D010
D010A
PIC16CR84, PIC16CR83 (Commercial, Industrial)
Conditions
4.0
4.5
1.5 *
—
—
6.0
5.5
—
—
0.05*
—
—
—
V
V
V
XT, RC and LP osc configuration
HS osc configuration
VSS
—
V
—
—
1.8
7.3
4.5
10
mA
mA
(During EEPROM programming)
HS OSC CONFIGURATION (PIC16CR84-10)
FOSC = 10 MHz, VDD = 5.5V
—
D013
5
10
mA
(3)
—
D020
IPD
Power-down Current
7.0
28
µA
—
D021
1.0
14
µA
—
D021A
1.0
16
µA
† Data in "Typ" column is at 5.0V, 25˚C unless otherwise stated. These parameters are for design guidance only
and are not tested.
4: For RC osc configuration, current through Rext is not included. The current through the resistor can be estimated by the formula IR = VDD/2Rext (mA) with Rext in kOhm.
DS30430B-page 87
PIC16F8X
13.2
DC CHARACTERISTICS:
PIC16LCR84, PIC16LCR83 (Commercial, Industrial)
DC Characteristics
Power Supply Pins
Parameter
No.
Sym
Characteristic
2.0
1.5 *
—
—
6.0
—
V
V
XT, RC, and LP osc configuration
—
VSS
—
V
0.05*
—
—
D010
D010A
—
—
1
7.3
4
10
mA
mA
D014
—
15
32
µA
D001
D002
VDD
VDR
D003
VPOR
D004
SVDD
IDD
Supply Voltage
RAM Data Retention
Voltage(1)
ensure internal Poweron Reset signal
internal Power-on
Reset signal
Supply Current(2)
Conditions
(During EEPROM programming)
FOSC = 32 kHz, VDD = 2.0V,
WDT disabled
IPD
D020
Power-down Current(3)
—
3.0
16
µA
D021
—
0.4
5.0
µA
D021A
—
0.4
6.0
µA
and are not tested.
4: For RC osc configuration, current through Rext is not included. The current through the resistor can be
estimated by the formula IR = VDD/2Rext (mA) with Rext in kOhm.
DS30430B-page 88
PIC16F8X
13.3
DC CHARACTERISTICS:
PIC16CR84A, PIC16CR83 (Commercial, Industrial)
PIC16LCR84, PIC16LCR83 (Commercial, Industrial)
Operating voltage VDD range as described in DC spec
Section 13.1 and Section 13.2.
DC Characteristics
All Pins Except
Power Supply Pins
Parameter
No.
Sym
VIL
D030
D030A
D031
D032
D033
D034
VIH
D040
D040A
D041
D042
Characteristic
Input Low Voltage
I/O ports
with TTL buffer
MCLR, RA4/T0CKI
OSC1 (XT, HS and LP modes)(1)
OSC1 (RC mode)
Input High Voltage
I/O ports
with TTL buffer
Min
Typ†
Max
Units
VSS
VSS
VSS
Vss
Vss
Vss
—
—
—
—
—
—
0.8
0.16VDD
0.2VDD
0.2VDD
0.3VDD
0.1VDD
V
V
V
V
V
V
4.5 V ≤ Vdd ≤ 5.5 V
entire range(4)
entire range
VDD
VDD
VDD
VDD
V
V
4.5 V ≤ VDD ≤ 5.5V
entire range(4)
entire range
—
—
VDD
V
V
250*
400*
2.4
0.48VDD
0.45VDD
0.85 VDD
—
—
—
D043
D050
VHYS
D070
IPURB
MCLR, RA4/T0CKI, OSC1
(RC mode)
OSC1 (XT, HS and LP modes)(1) 0.7 VDD
Hysteresis of
TBD
Schmitt Trigger inputs
PORTB weak pull-up current
50*
D060
IIL
Input Leakage Current(2,3)
I/O ports
—
—
±1
MCLR, RA4/T0CKI
OSC1
—
—
—
—
±5
±5
D061
D063
—
—
—
Conditions
V
µA VDD = 5.0V, VPIN = VSS
µA Vss ≤ VPIN ≤ VDD,
Pin at hi-impedance
µA Vss ≤ VPIN ≤ VDD
µA Vss ≤ VPIN ≤ VDD, XT, HS and
Output Low Voltage
—
—
I/O ports
0.6
V IOL = 8.5 mA, VDD = 4.5V
—
—
OSC2/CLKOUT
0.6
V IOL = 1.6 mA, VDD = 4.5V
Output High Voltage
—
—
D090
VOH
I/O ports(3)
VDD-0.7
V IOH = -3.0 mA, VDD = 4.5V
—
—
D092
OSC2/CLKOUT
VDD-0.7
V IOH = -1.3 mA, VDD = 4.5V
*
and are not tested.
Note 1: In RC oscillator configuration, the OSC1 pin is a Schmitt Trigger input. Do not drive the PIC16CR8X with an
external clock while the device is in RC mode, otherwise chip damage may result.
2: The leakage current on the MCLR pin is strongly dependent on the applied voltage level. The specified levels represent normal operating conditions. Higher leakage current may be measured at different input voltages.
3: Negative current is defined as coming out of the pin.
4: The user may use better of the two specs.
D080
D083
VOL
DS30430B-page 89
PIC16F8X
13.4
DC CHARACTERISTICS:
PIC16CR84A, PIC16CR83 (Commercial, Industrial)
PIC16LCR84A, PIC16LCR83 (Commercial, Industrial)
DC Characteristics
All Pins Except
Power Supply Pins
Parameter
No.
Sym
D100
COSC2
D101
CIO
D120
D121
ED
VDRW
Characteristic
Capacitive Loading Specs
on Output Pins
OSC2 pin
All I/O pins and OSC2
(RC mode)
Data EEPROM Memory
Endurance
VDD for read/write
Operating voltage VDD range as described in DC spec Section 13.1
and Section 13.2.
Min
Typ†
Max Units
Conditions
—
—
15
pF
—
—
50
pF
1M
VMIN
10M
—
In XT, HS and LP modes when
external clock is used to drive
OSC1.
E/W 25°C at 5V
voltage
—
—
D122
TDEW Erase/Write cycle time
10
ms
and are not tested.
DS30430B-page 90
—
6.0
PIC16F8X
TABLE 13-2:
TIMING PARAMETER SYMBOLOGY
The timing parameter symbols have been created following one of the following formats:
1. TppS2ppS
2. TppS
T
F
Frequency
Lowercase symbols (pp) and their meanings:
pp
2
to
ck
CLKOUT
cy
cycle time
io
I/O port
inp
INT pin
mc
MCLR
Uppercase symbols and their meanings:
S
F
Fall
H
High
I
Invalid (Hi-impedance)
L
Low
T
Time
os,osc
ost
pwrt
rbt
t0
wdt
OSC1
oscillator start-up timer
power-up timer
RBx pins
T0CKI
watchdog timer
P
R
V
Z
Period
Rise
Valid
High Impedance
FIGURE 13-1: PARAMETER MEASUREMENT INFORMATION
All timings are measure between high and low measurement points as indicated in the figures below.
0.7 VDD XTAL
0.8 VDD RC (High)
0.9 VDD (High)
0.3 VDD XTAL
0.15 VDD RC (Low)
OSC1 Measurement Points
0.1 VDD (Low)
I/O Port Measurement Points
FIGURE 13-2: LOAD CONDITIONS
Load Condition 1
Load Condition 2
VDD/2
RL
CL
Pin
CL
Pin
VSS
VSS
RL =
464Ω
CL =
50 pF
for all pins except OSC2.
15 pF
for OSC2 output.
DS30430B-page 91
PIC16F8X
13.5
Timing Diagrams and Specifications
FIGURE 13-3: EXTERNAL CLOCK TIMING
Q4
Q1
Q3
Q2
Q4
Q1
OSC1
1
3
3
4
4
2
CLKOUT
TABLE 13-3:
Parameter
No.
1
EXTERNAL CLOCK TIMING REQUIREMENTS
Sym
Characteristic
Min
Typ†
Max
Units Conditions
FOSC
External CLKIN Frequency(1)
DC
DC
DC
DC
—
—
—
—
2
4
10
200
MHz
MHz
MHz
kHz
XT, RC osc
XT, RC osc
HS osc
LP osc
PIC16LCR8X-04
PIC16CR8X-04
PIC16CR8X-10
PIC16LCR8X-04
Oscillator Frequency(1)
DC
DC
0.1
0.1
1.0
DC
—
—
—
—
—
—
2
4
2
4
10
200
MHz
MHz
MHz
MHz
MHz
kHz
RC osc
RC osc
XT osc
XT osc
HS osc
LP osc
PIC16LCR8X-04
PIC16CR8X-04
PIC16LCR8X-04
PIC16CR8X-04
PIC16CR8X-10
PIC16LCR8X-04
External CLKIN Period(1)
500
250
100
5.0
—
—
—
—
—
—
—
—
ns
ns
ns
µs
XT, RC osc
XT, RC osc
HS osc
LP osc
PIC16LCR8X-04
PIC16CR8X-04
PIC16CR8X-10
PIC16LCR8X-04
Oscillator Period(1)
500
250
500
250
100
5.0
—
—
—
—
—
—
—
—
10,000
10,000
1,000
—
ns
ns
ns
ns
ns
µs
RC osc
RC osc
XT osc
XT osc
HS osc
LP osc
PIC16LCR8X-04
PIC16CR8X-04
PIC16LCR8X-04
PIC16CR8X-04
PIC16CR8X-10
PIC16LCR8X-04
0.4
60 *
50 *
2.0 *
35 *
25 *
50 *
15 *
4/Fosc
—
—
—
—
—
—
—
DC
—
—
—
—
—
—
—
µs
ns
ns
µs
ns
ns
ns
ns
XT osc
XT osc
LP osc
HS osc
XT osc
LP osc
HS osc
PIC16LCR8X-04
PIC16CR8X-04
PIC16LCR8X-04
PIC16CR8X-10
PIC16CR8X-04
PIC16LCR8X-04
PIC16CR8X-10
Tosc
2
3
TCY
TosL,
TosH
Instruction Cycle Time(1)
Clock in (OSC1) High or Low
Time
4
TosR,
TosF
Clock in (OSC1) Rise or Fall Time
*
†
Data in "Typ" column is at 5.0V, 25°C unless otherwise stated. These parameters are for design guidance only
and are not tested.
Note 1: Instruction cycle period (TCY) equals four times the input oscillator time base period. All specified values are
based on characterization data for that particular oscillator type under standard operating conditions with the
device executing code. Exceeding these specified limits may result in an unstable oscillator operation and/or
higher than expected current consumption. All devices are tested to operate at "min." values with an
external clock applied to the OSC1 pin.
When an external clock input is used, the "Max." cycle time limit is "DC" (no clock) for all devices.
DS30430B-page 92
PIC16F8X
FIGURE 13-4: CLKOUT AND I/O TIMING
Q1
Q4
Q2
Q3
OSC1
11
10
22
23
CLKOUT
13
19
14
12
18
16
I/O Pin
(input)
15
17
I/O Pin
(output)
new value
old value
20, 21
Note: All tests must be done with specified capacitive loads (Figure 13-2) 50 pF on I/O pins and CLKOUT.
TABLE 13-4:
Parameter
No.
10
CLKOUT AND I/O TIMING REQUIREMENTS
Sym
Characteristic
TosH2ckL
OSC1↑ to CLKOUT↓
10A
11
TosH2ckH
OSC1↑ to CLKOUT↑
11A
12
TckR
CLKOUT rise time
12A
13
TckF
CLKOUT fall time
13A
Min
Typ†
Max
Units Conditions
PIC16CR8X
—
15
30 *
ns
Note 1
PIC16LCR8X
—
15
120 *
ns
Note 1
PIC16CR8X
—
15
30 *
ns
Note 1
PIC16LCR8X
—
15
120 *
ns
Note 1
PIC16CR8X
—
15
30 *
ns
Note 1
PIC16LCR8X
—
15
100 *
ns
Note 1
PIC16CR8X
—
15
30 *
ns
Note 1
PIC16LCR8X
—
15
100 *
ns
Note 1
14
TckL2ioV
CLKOUT ↓ to Port out valid
—
—
0.5TCY +20 *
ns
Note 1
15
TioV2ckH
Port in valid before
PIC16CR8X
0.30TCY + 30 *
—
—
ns
Note 1
CLKOUT ↑
PIC16LCR8X
0.30TCY + 80 *
—
—
ns
Note 1
16
TckH2ioI
Port in hold after CLKOUT ↑
0*
—
—
ns
Note 1
17
TosH2ioV
OSC1↑ (Q1 cycle) to
PIC16CR8X
—
—
125 *
ns
Port out valid
PIC16LCR8X
—
—
250 *
ns
18
TosH2ioI
OSC1↑ (Q2 cycle) to Port input invalid
(I/O in hold time)
TBD
—
—
ns
19
TioV2osH
Port input valid to OSC1↑
(I/O in setup time)
TBD
—
—
ns
20
TioR
Port output rise time
20A
21
TioF
Port output fall time
21A
22
Tinp
22A
23
23A
Trbp
PIC16CR8X
—
10
25 *
ns
PIC16LCR8X
—
10
60 *
ns
PIC16CR8X
—
10
25 *
ns
PIC16LCR8X
—
10
60 *
ns
INT pin high
PIC16CR8X
20 *
—
—
ns
or low time
PIC16LCR8X
55 *
—
—
ns
RB7:RB4 change INT
PIC16CR8X
TOSC §
—
—
ns
high or low time
PIC16LCR8X
TOSC §
—
—
ns
*
†
Data in "Typ" column is at 5.0V, 25°C unless otherwise stated. These parameters are for design guidance only
and are not tested.
§ By design
Note 1: Measurements are taken in RC Mode where CLKOUT output is 4 x TOSC.
DS30430B-page 93
PIC16F8X
FIGURE 13-5: RESET, WATCHDOG TIMER, OSCILLATOR START-UP TIMER AND POWER-UP
TIMER TIMING
VDD
MCLR
30
Internal
POR
33
PWRT
Time-out
32
OSC
Time-out
Internal
RESET
Watchdog
Timer
RESET
31
34
34
I/O Pins
TABLE 13-5:
RESET, WATCHDOG TIMER, OSCILLATOR START-UP TIMER AND POWER-UP
TIMER REQUIREMENTS
Parameter
No.
Sym
Characteristic
30
TmcL
MCLR Pulse Width (low)
31
Twdt
Watchdog Timer Time-out Period
(No Prescaler)
32
Tost
Oscillation Start-up Timer Period
33
Tpwrt
34
TIOZ
*
†
Power-up Timer Period
I/O Hi-impedance from MCLR Low
or reset
Min
Typ†
Max
Units
1000 *
—
—
ns
2.0V ≤ VDD ≤ 6.0V
7*
18
33 *
ms
VDD = 5.0V
ms
TOSC = OSC1 period
VDD = 5.0V
1024TOSC
28 *
72
132 *
ms
—
—
100 *
ns
Conditions
Data in "Typ" column is at 5V, 25°C unless otherwise stated. These parameters are for design guidance only and are not
tested.
DS30430B-page 94
PIC16F8X
FIGURE 13-6: TIMER0 CLOCK TIMINGS
RA4/T0CKI
40
41
42
TABLE 13-6:
Parameter
No.
40
TIMER0 CLOCK REQUIREMENTS
Sym Characteristic
Tt0H T0CKI High Pulse Width
Min
No Prescaler
With Prescaler
41
Tt0L T0CKI Low Pulse Width
No Prescaler
With Prescaler
42
*
†
Tt0P T0CKI Period
Typ† Max Units Conditions
0.5TCY + 20 *
—
—
ns
50 *
30 *
—
—
—
—
ns
ns
0.5TCY + 20 *
—
—
ns
50 *
20 *
—
—
—
—
ns
ns
2.0V ≤ VDD ≤ 3.0V
3.0V ≤ VDD ≤ 6.0V
TCY + 40 *
N
—
—
ns
N = prescale value
(2, 4, ..., 256)
2.0V ≤ VDD ≤ 3.0V
3.0V ≤ VDD ≤ 6.0V
Data in "Typ" column is at 5.0V, 25°C unless otherwise stated. These parameters are for design guidance only and are not
tested.
DS30430B-page 95
PIC16F8X
NOTES:
DS30430B-page 96
PIC16F8X
14.0
DC & AC CHARACTERISTICS GRAPHS/TABLES FOR PIC16CR83 AND
PIC16CR84
NOT AVAILABLE AT THIS TIME.
DS30430B-page 97
PIC16F8X
NOTES:
DS30430B-page 98
PIC16F8X
15.0
PACKAGING INFORMATION
15.1
Package Marking Information
Example
18L PDIP
MMMMMMMMMMMMXXX
MMMMMMMMXXXXXXXX
PIC16F84
10I/P
9305 CBA
AABB CDE
18L SOIC
Example
MMMMMMMM
XXXXXXXX
AABB CDE
PIC16LF84
04I/S0218
9310 CBA
Legend: MM...M
XX...X
AA
BB
C
Microchip part number information
Customer specific information*
Year code (last two digits of calendar year)
Week code (week of January 1 is week ‘01’)
Facility code of the plant at which wafer is manufactured
C = Chandler, Arizona, U.S.A.,
S = Tempe, Arizona, U.S.A.
D
Mask revision number
E
Assembly code of the plant or country of origin in which
part was assembled
Note: In the event the full Microchip part number cannot be marked on one line,
it will be carried over to the next line thus limiting the number of available
characters for customer specific information.
*
Standard OTP marking consists of Microchip part number, year code, week
code, facility code, mask rev#, and assembly code. For OTP marking beyond
this, certain price adders apply. Please check with your Microchip Sales Office.
For QTP devices, any special marking adders are included in QTP price.
DS30430B-page 99
PIC16F8X
15.2
18-Lead Plastic Dual In-line (PDIP) - 300 mil
N
α
C
E1 E
eA
eB
Pin No. 1
Indicator
Area
D
S
S1
Base
Plane
Seating
Plane
L
B1
A1 A2 A
e1
B
D1
Package Group: Plastic Dual In-Line (PLA)
Millimeters
Symbol
Min
Max
α
0°
A
A1
A2
B
B1
C
D
D1
E
E1
e1
eA
eB
L
N
S
S1
–
0.381
3.048
0.355
1.524
0.203
22.479
20.320
7.620
6.096
2.489
7.620
7.874
3.048
18
0.889
0.127
DS30430B-page 100
Inches
Notes
Min
Max
10°
0°
10°
4.064
–
3.810
0.559
1.524
0.381
23.495
20.320
8.255
7.112
2.591
7.620
9.906
3.556
18
–
–
–
0.015
0.120
0.014
0.060
0.008
0.885
0.800
0.300
0.240
0.098
0.300
0.310
0.120
18
0.035
0.005
0.160
–
0.150
0.022
0.060
0.015
0.925
0.800
0.325
0.280
0.102
0.300
0.390
0.140
18
–
–
Reference
Typical
Reference
Typical
Reference
Notes
Reference
Typical
Reference
Typical
Reference
PIC16F8X
15.3
18-Lead Plastic Surface Mount (SOIC) - 300 mil
e
B
h x 45°
N
Index
Area
E
H
α
C
Chamfer
h x 45°
L
1
2
3
D
Seating
Plane
Base
Plane
CP
A1
A
Package Group: Plastic SOIC (SO)
Millimeters
Symbol
Min
Max
Inches
Notes
Min
Max
α
0°
8°
0°
8°
A
A1
B
C
D
E
e
H
h
L
N
CP
2.362
0.101
0.355
0.241
11.353
7.416
1.270
10.007
0.381
0.406
18
–
2.642
0.300
0.483
0.318
11.735
7.595
1.270
10.643
0.762
1.143
18
0.102
0.093
0.004
0.014
0.009
0.447
0.292
0.050
0.394
0.015
0.016
18
–
0.104
0.012
0.019
0.013
0.462
0.299
0.050
0.419
0.030
0.045
18
0.004
Reference
Notes
Reference
DS30430B-page 101
PIC16F8X
NOTES:
DS30430B-page 102
PIC16F8X
APPENDIX A: FEATURE
IMPROVEMENTS
The following is the list of feature improvements over
the PIC16C5X microcontroller family:
1.
2.
3.
4.
5.
6.
7.
8.
9.
10.
11.
12.
13.
14.
15.
Instruction word length is increased to 14 bits.
This allows larger page sizes both in program
memory (2K now as opposed to 512 before) and
the register file (128 bytes now versus 32 bytes
before).
A PC latch register (PCLATH) is added to handle program memory paging. PA2, PA1 and PA0
bits are removed from the status register and
placed in the option register.
Data memory paging is redefined slightly. The
STATUS register is modified.
Four new instructions have been added:
RETURN, RETFIE, ADDLW, and SUBLW. Two
instructions, TRIS and OPTION, are being
phased out although they are kept for
compatibility with PIC16C5X.
OPTION and TRIS registers are made
addressable.
Interrupt capability is added. Interrupt vector is
at 0004h.
Stack size is increased to 8 deep.
Reset vector is changed to 0000h.
Reset of all registers is revisited. Five different
reset (and wake-up) types are recognized.
Registers are reset differently.
Wake up from SLEEP through interrupt is
added.
Two separate timers, the Oscillator Start-up
Timer (OST) and Power-up Timer (PWRT), are
included for more reliable power-up. These
timers are invoked selectively to avoid
unnecessary delays on power-up and wake-up.
PORTB has weak pull-ups and interrupt on
change features.
T0CKI pin is also a port pin (RA4/T0CKI).
FSR is a full 8-bit register.
"In system programming" is made possible. The
user can program PIC16FXX devices using only
five pins: VDD, VSS, VPP, RB6 (clock) and RB7
(data in/out).
APPENDIX B: COMPATIBILITY
To convert code written for PIC16C5X to PIC16F8X,
the user should take the following steps:
1.
2.
3.
4.
5.
Remove any program memory page select
operations (PA2, PA1, PA0 bits) for CALL, GOTO.
Revisit any computed jump operations (write to
PC or add to PC, etc.) to make sure page bits
are set properly under the new scheme.
Eliminate any data memory page switching.
Redefine data variables for reallocation.
Verify all writes to STATUS, OPTION, and FSR
registers since these have changed.
Change reset vector to 0000h.
DS30430B-page 103
PIC16F8X
APPENDIX C: WHAT’S NEW
Not applicable - new document.
APPENDIX D: WHAT’S CHANGES
Not applicable - new document.
APPENDIX E: PIC16C84 TO
PIC16F83/CR83 AND
PIC16F84/CR84
CONVERSION
CONSIDERATIONS
This appendix discusses some of the issues that you
may encounter as you convert your design from a
PIC16C84 to a PIC16F83 or PIC16F84 device. These
new devices are:
•
•
•
•
PIC16F83
PIC16CR83
PIC16F84
PIC16CR84
Some of the issues that may be encountered are:
1.
2.
3.
4.
DS30430B-page 104
The polarity of the PWRTE configuration bit has
been reversed. Ensure that the programmer has
this bit correctly set before programming.
The PIC16F84 and PIC16CR84 have larger
RAM sizes. Ensure that this does not cause an
issue with your program.
The MCLR pin now has an on-chip filter. The
input signal on the MCLR pin will require a
longer low pulse to generate an interrupt.
Many electrical specifications have been
improved. Compare the electrical specifications
of the two devices to ensure that this will not
cause a compatibility issue.
PIC14000
20
o
em
y
or
(x
)
r
wo
2
/I
I
SP
C
,U
T)
R
SA
Peripherals
g
in
m
am
4K
192
s
te
by
TMR0
I2C/
ADTMR SMBus
M
14
11
22
2.7-6.0
Internal Oscillator,
Bandgap Reference,
Temperature Sensor,
Calibration Factors,
Yes Low Voltage Detector,
SLEEP, HIBERNATE,
Comparators with
Programmable References
(2)
)
r
ts
gr
ol
rte nels
p
ro
V
s
e
(
)
P
m
hi
e
v
n
s
l
a
(
-c
rc
ia
ue
on ha
)(
e(
ge
y
gr
n
u
l
r
q
r
s
n
o
C
o
u
e
e
C
o
t(
a
S
lO
Pr
D )
Fr
R
od
or
tS
em
pt ins
na res
A/ -res
e
M
M
ui
u
lP
o
um
M
g
c
i
r
r
e
O
r
u
t
a
r
h
i
e
im
ri
R
ta
lta
di at
op ig
te /O P
m
-C
ax
Se
In
Sl (h
EP
I
Vo
Da
Ti
Ad Fe
M
In
y
nc
r
pe
fO
n
io
at
14
Memory
)
ds
Pa
a
ck
ge
s
28-pin DIP, SOIC, SSOP
(.300 mil)
Features
F.1
)
Hz
(M
Clock
PIC16F8X
APPENDIX F: PIC16/17 MICROCONTROLLERS
PIC14000 Devices
DS30430B-page 105
20
20
20
20
20
20
20
20
PIC16C54A
PIC16CR54A
PIC16C55
PIC16C56
PIC16C57
PIC16CR57B
PIC16C58A
PIC16CR58A
im
um
qu
—
2K
—
2K
1K
512
—
512
RO
en
2K
—
2K
—
—
—
512
—
—
—
73
73
72
72
25
24
25
25
25
25
RA
D
M
M
at
a
Fr
e
512
yte
s)
em
or
TMR0
TMR0
TMR0
TMR0
TMR0
TMR0
TMR0
TMR0
TMR0
TMR0
)
12
12
20
20
12
20
12
12
12
12
ns
2.5-6.25
2.0-6.25
2.5-6.25
2.5-6.25
2.5-6.25
2.5-6.25
2.0-6.25
2.0-6.25
2.5-6.25
2.5-6.25
e
33
33
33
33
33
33
33
33
33
33
ng
M
cy
of
O
p
er
at
ion
P
(
r
M
og
Hz
(x ram
)
12 M
wo em
rd or
s) y
OM
EP
R
384
y(
b
Ti
m
M
er
(s
le
od
u
Peripherals
es
s
In
ax
18-pin DIP, SOIC; 20-pin SSOP
18-pin DIP, SOIC
Features
All PIC16/17 Family devices have Power-On Reset, selectable Watchdog Timer, selectable code protect and high I/O current capability.
4
20
PIC16C54
M
PIC16C52
Pi
I/O
on
cti
Memory
e
)
Nu
Ra
ag
Vo
lt
lts
(V
o
m
be
r
of
str
u
P
DS30430B-page 106
ag
F.2
ac
k
Clock
PIC16F8X
PIC16C5X Family of Devices
20
20
20
20
20
PIC16C556
PIC16C558
PIC16C620
PIC16C621
PIC16C622
2K
1K
512
2K
1K
512
128
80
80
128
80
80
TMR0
TMR0
TMR0
TMR0
TMR0
TMR0
H
2
2
2
—
—
—
Yes
Yes
Yes
—
—
—
3
4
4
4
3
3
13
13
13
13
13
13
2.5-6.0
2.5-6.0
2.5-6.0
2.5-6.0
2.5-6.0
2.5-6.0
Yes
Yes
Yes
—
—
—
et
es
R
R
es
ut
-o
ag
ge
n
k
a
c
lt
ow
Pa
Vo
Br
e
g
an
)
ts
ol
(V
Features
All PIC16/17 Family devices have Power-on Reset, selectable Watchdog Timer, selectable code protect and high I/O
current capability.
All PIC16C6XXX Family devices use serial programming with clock pin RB6 and data pin RB7.
20
PIC16C554
(M
Peripherals
y
or
em s)
M rd
ge
ra
o
lta
pe
am 4 w
o
r
O
V
s)
of
og x1
e
te
y
s
Pr (
nc
nc
by
s)
ce
(
e
(
e
y
s)
ur
le
er
qu
r
(
f
o
r
u
e
o
o
Fr
Re
od
tS
at
em
M
M
al
ns
ar
up
um
M
r
n
r
O
p
r
r
Pi
e
im
ta
R
m
te
te
m
a
ax
O
i
P
o
n
n
/
I
I
I
D
T
E
M
C
n
tio
Memory
F.3
z)
Clock
PIC16F8X
PIC16CXXX Family of Devices
DS30430B-page 107
DS30430B-page 108
20
20
20
20
20
PIC16CR63(1)
PIC16C64
PIC16C64A(1)
PIC16CR64(1)
PIC16C65
Features
—
4K
4K
—
2K
2K
—
4K
—
2K
2K
4K
—
—
2K
—
—
4K
—
2K
—
—
192 TMR0,
TMR1, TMR2
192 TMR0,
TMR1, TMR2
192 TMR0,
TMR1, TMR2
128 TMR0,
TMR1, TMR2
128 TMR0,
TMR1, TMR2
128 TMR0,
TMR1, TMR2
192 TMR0,
TMR1, TMR2
192 TMR0,
TMR1, TMR2
128 TMR0,
TMR1, TMR2
128 TMR0,
TMR1, TMR2
128 TMR0,
TMR1, TMR2
H
2 SPI/I2C, Yes
USART
11
11
11
2 SPI/I2C, Yes
USART
2 SPI/I2C, Yes
USART
8
8
8
10
10
7
7
7
Yes
1 SPI/I2C
Yes
Yes
1 SPI/I2C
1 SPI/I2C
—
—
2 SPI/I2C,
USART
2 SPI/I2C,
USART
—
—
—
1 SPI/I2C
1 SPI/I2C
1 SPI/I2C
33
33
33
33
33
33
22
22
22
22
22
2.5-6.0
2.5-6.0
3.0-6.0
2.5-6.0
2.5-6.0
3.0-6.0
2.5-6.0
2.5-6.0
2.5-6.0
2.5-6.0
3.0-6.0
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
28-pin SDIP, SOIC, SSOP
40-pin DIP;
44-pin PLCC, MQFP
40-pin DIP;
44-pin PLCC, MQFP
Yes 40-pin DIP;
44-pin PLCC, MQFP, TQFP
Yes 40-pin DIP;
—
Yes 40-pin DIP;
Yes 40-pin DIP;
—
Yes 28-pin SDIP, SOIC
Yes 28-pin SDIP, SOIC, SSOP
—
All PIC16/17 family devices have Power-on Reset, selectable Watchdog Timer, selectable code protect, and high I/O current capability.
20
20
PIC16C63
PIC16CR65(1)
20
PIC16CR62(1)
20
20
PIC16C62A(1)
PIC16C65A(1)
20
PIC16C62
(M
s)
Peripherals
y
(
or
le
T)
m )
g
du
e
s
o
in
i
AR
t
M
d
a
M
r
m
S
r
o
m
e
U
m
M
p
a w
,
)
a
O
)
2C
W
gr 4
ts
gr
of
ol
/I
/P
t
es
ro (x1
ro
I
t
r
y
e
V
P
y
s
P
r
o
P
)
(
et
e
l
nc
S
P
(b
(s
pa
rc
ge
e
ue
es
y
ria
)(
le
u
r
m
q
v
n
s
e
R
u
o
e
o
a
la
rt(
So
Fr
R
ut
tS
od
/C
es
em
lS
ui
pt ins
e
M
M
-o
Po
re
e
c
M
l
um
u
l
g
n
ag
r
u
l
r
O
r
i
t
a
a
k
e
r
P
m
a
a
w
i
M
t
i
R
p
t
l
c
r
r
C
o
m
te
ax
Se
Da
In
In
Br
Pa
Ca
EP
RO
Ti
Pa
Vo
I/O
M
on
Memory
F.4
z)
Clock
PIC16F8X
(M
14
rd
wo
Memory
M
e(
ul
od
R
SA
T)
Peripherals
s)
ls
ne
n
ha
Features
1K
20
20
20
20
20
20
PIC16C72
PIC16C73
PIC16C73A(1)
PIC16C74
PIC16C74A(1)
—
—
—
8
8
192 TMR0,
2 SPI/I2C, Yes
TMR1, TMR2
USART
192 TMR0,
2 SPI/I2C, Yes
TMR1, TMR2
USART
5
5
5
4
4
4
—
192 TMR0,
2 SPI/I2C,
TMR1, TMR2
USART
—
—
—
—
192 TMR0,
2 SPI/I2C,
TMR1, TMR2
USART
—
—
—
—
TMR0
TMR0
TMR0
128 TMR0,
1 SPI/I2C
TMR1, TMR2
68
36
36
12
12
11
11
8
4
4
4
33
33
22
22
22
13
13
13
2.5-6.0
2.5-6.0
2.5-6.0
2.5-6.0
2.5-6.0
2.5-6.0
2.5-6.0
2.5-6.0
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
18-pin DIP, SOIC
28-pin SDIP, SOIC
40-pin DIP;
44-pin PLCC, MQFP
Yes 40-pin DIP;
—
—
Yes 18-pin DIP, SOIC;
20-pin SSOP
—
Yes 18-pin DIP, SOIC;
20-pin SSOP
All PIC16/17 Family devices have Power-on Reset, selectable Watchdog Timer, selectable code protect and high I/O current
capability.
All PIC16C7X Family devices use serial programming with clock pin RB6 and data pin RB7.
4K
4K
4K
4K
2K
1K
20
PIC16C71
PIC16C711
512
20
PIC16C710
y
or
(x
g
in
m
U
m
,
M 2C
C
)
a
O
ts
W
it)
gr
s)
em
of
ol
/P PI/I
rt
te
-b
ro
y
M
V
s
e
y
o
c
8
(
)
P
r
(
S
P
et
l
ce
(b
(s
en
am
pa s) (
e
ge
er
y
es
ur
le
ria
t
gr
qu
r
v
n
r
m
o
u
(
e
o
e
R
o
t
a
o
la
ve
Pr
Fr
R
od
or
tS s
es
ut
tS
/C
em
lS
M
e
M
ui
on rup
-o
n
re al P
ag
um
le
M
i
g
c
r
O
l
n
C
r
u
k
r
a
i
i
m
P
e
R
i
c
r
ra
ta
lt
pt
D
te
ow
m
-C
ax
EP
Pa
Se
In
A/
Pa
I/O
Vo
Da
Ti
M
In
Br
Ca
p
a
er
n
tio
s)
F.5
)
Hz
Clock
PIC16F8X
DS30430B-page 109
10
10
10
10
PIC16F84(1)
PIC16CR84(1)
PIC16F83(1)
PIC16CR83(1)
F
—
512
—
1K
—
—
—
—
—
1K
—
1K
—
—
512
EE
(M
36
36
68
68
Da
64
64
64
64
ta
Da
em
64
ta
y
or
P
(
er
T
TMR0
TMR0
TMR0
TMR0
o
M
4
4
4
4
4
Peripherals
)
ts
ol
(V
Features
13
13
13
13
13
s
ce
ge
ur
o
an
S
R
es
pt ins
ge
ag
ru
a
k
r
P
lt
c
te
In
Pa
Vo
I/O
s)
e(
l
du
)
es
t
by
Memory
im
TMR0
EE
M
RO
s)
e
yt
(b
y
or
em
M
M
am
r
og
Pr
36
M
RO
M
ra
pe
O
O
PR
of
n
tio
)
Hz
All PIC16/17 family devices have Power-on Reset, selectable Watchdog Timer, selectable code protect, and
high I/O current capability.
10
PIC16C84
a
M
um
xim
cy
n
ue
q
re
h
DS30430B-page 110
as
F.6
Fl
Clock
PIC16F8X
y
or
em
M
M
T)
R
SA
)
(s
le
u
od
ls
ne
n
ha
Features
4K
8
PIC16C924
176 TMR0,
1 SPI/I2C
TMR1, TMR2
176 TMR0,
1 SPI/I2C
TMR1, TMR2
am
—
—
5
—
4 Com
32 Seg
4 Com
32 Seg
,U
9
8
25
25
27
27
3.0-6.0
3.0-6.0
Yes
Yes
—
—
64-pin SDIP(1), TQFP,
68-pin PLCC, DIE
64-pin SDIP(1), TQFP,
68-pin PLCC, DIE
All PIC16/17 Family devices have Power-on Reset, selectable Watchdog Timer, selectable code protect and high I/O current capability.
All PIC16CXX Family devices use serial programming with clock pin RB6 and data pin RB7.
1: Please contact your local Microchip representative for availability of this package.
4K
8
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PIC16C9XX Family Of Devices
DS30430B-page 111
25
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40-pin DIP;
44-pin PLCC, TQFP, MQFP
40-pin DIP;
40-pin DIP;
40-pin DIP;
40-pin DIP;
40-pin DIP;
44-pin PLCC, MQFP
All PIC16/17 Family devices have Power-on Reset, selectable Watchdog Timer, selectable code protect and high I/O current capability.
25
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DS30430B-page 112
ag
F.8
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k
Clock
PIC16F8X
PIC17CXX Family of Devices
PIC16F8X
PIN COMPATIBILITY
Devices that have the same package type and VDD,
VSS and MCLR pin locations are said to be pin
compatible. This allows these different devices to
operate in the same socket. Compatible devices may
only requires minor software modification to allow
proper operation in the application socket
(ex., PIC16C56 and PIC16C61 devices). Not all
devices in the same package size are pin compatible;
for example, the PIC16C62 is compatible with the
PIC16C63, but not the PIC16C55.
Pin compatibility does not mean that the devices offer
the same features. As an example, the PIC16C54 is
pin compatible with the PIC16C71, but does not have
an A/D converter, weak pull-ups on PORTB, or
interrupts.
TABLE F-1:
PIN COMPATIBLE DEVICES
Pin Compatible Devices
Package
PIC12C508, PIC12C509
8-pin
PIC16C54, PIC16C54A,
PIC16CR54A,
PIC16C56,
PIC16C58A, PIC16CR58A,
PIC16C61,
PIC16C554, PIC16C556, PIC16C558
PIC16C620, PIC16C621, PIC16C622,
PIC16C710, PIC16C71, PIC16C711,
PIC16F83, PIC16CR83,
PIC16C84, PIC16F84A, PIC16CR84
18-pin
20-pin
PIC16C55,
PIC16C57, PIC16CR57B
28-pin
PIC16C62, PIC16CR62, PIC16C62A, PIC16C63,
PIC16C72, PIC16C73, PIC16C73A
28-pin
PIC16C64, PIC16CR64, PIC16C64A,
PIC16C65, PIC16C65A,
PIC16C74, PIC16C74A
40-pin
PIC17C42, PIC17CR42, PIC17C42A,
PIC17C43, PIC17CR43, PIC17C44
40-pin
PIC16C923, PIC16C924
64/68-pin
DS30430B-page 113
PIC16F8X
NOTES:
DS30430B-page 114
PIC16F8X
INDEX
Interrupts .............................................................. 37, 48
A
L
Absolute Maximum Ratings ..........................................71, 85
ALU .......................................................................................7
Architectural Overview ..........................................................7
Assembler ...........................................................................68
Loading of PC..................................................................... 18
B
Block Diagram
Interrupt Logic ............................................................. 48
On-Chip Reset Circuit ................................................. 42
RA3:RA0 and RA5 Port Pins ...................................... 21
RA4 Pin....................................................................... 21
RB7:RB4 Port Pins ..................................................... 23
TMR0/WDT Prescaler................................................. 30
Watchdog Timer.......................................................... 51
Brown-out Protection Circuit ...............................................47
C
C Compiler (MP-C) .............................................................69
Carry .....................................................................................7
CLKIN ...................................................................................9
CLKOUT ...............................................................................9
Code Protection ............................................................37, 53
Compatibility, upward............................................................3
Computed GOTO................................................................18
Configuration Bits................................................................37
M
MCLR ....................................................................... 9, 42, 43
Memory Organization
Data Memory .............................................................. 12
Memory Organization ................................................. 11
Program Memory........................................................ 11
MPASM Assembler ...................................................... 67, 68
MP-C C Compiler ............................................................... 69
MPSIM Software Simulator .......................................... 67, 69
O
OPTION.................................................................. 16, 43, 49
OSC Selection .................................................................... 37
OSC.................................................................................... 19
OSC.................................................................................... 29
Oscillator
HS......................................................................... 39, 47
LP ......................................................................... 39, 47
Oscillator Configurations .................................................... 39
P
Family of Devices
PIC14000 .................................................................. 105
PIC16C5X ................................................................. 106
PIC16CXXX .............................................................. 107
PIC16C6X ................................................................. 108
PIC16C7X ................................................................. 109
PIC16C8X ............................................................. 3, 110
PIC16C9XX............................................................... 111
PIC17CXX................................................................. 112
FSR...............................................................................19, 43
Fuzzy Logic Dev. System (fuzzyTECH-MP) ...............67, 69
Paging, Program Memory................................................... 18
PCL............................................................................... 18, 43
PCLATH ....................................................................... 18, 43
PD........................................................................... 15, 42, 47
PICDEM-1 Low-Cost PIC16/17 Demo Board ............... 67, 68
PICDEM-2 Low-Cost PIC16CXX Demo Board............. 67, 68
PICDEM-3 Low-Cost PIC16C9XXX Demo Board .............. 68
PICMASTER RT In-Circuit Emulator................................ 67
PICSTART Low-Cost Development System .................... 67
Pin Compatible Devices ................................................... 113
Pinout Descriptions............................................................... 9
POR.................................................................................... 44
Oscillator Start-up Timer (OST)............................ 37, 44
Power-on Reset (POR)................................... 37, 43, 44
Power-up Timer (PWRT) ...................................... 37, 44
Time-out Sequence .................................................... 47
Time-out Sequence on Power-up............................... 45
TO................................................................... 15, 42, 47
Port RB Interrupt................................................................. 49
PORTA ..................................................................... 9, 21, 43
PORTB ..................................................................... 9, 23, 43
Power-down Mode (SLEEP)............................................... 52
Prescaler ............................................................................ 29
PRO MATE Universal Programmer.................................. 67
Product Identification System ........................................... 121
G
R
GIE......................................................................................48
RBIF bit......................................................................... 23, 49
RC Oscillator .......................................................... 39, 41, 47
Read-Modify-Write.............................................................. 25
Register File ....................................................................... 12
Reset ............................................................................ 37, 42
Reset on Brown-Out ........................................................... 47
D
DC Characteristics ....................73, 74, 75, 76, 87, 88, 89, 90
Development Support .........................................................67
Development Tools .............................................................67
Digit Carry .............................................................................7
E
Electrical Characteristics...............................................71, 85
External Power-on Reset Circuit ........................................44
F
I
I/O Ports..............................................................................21
I/O Programming Considerations........................................25
In-Circuit Serial Programming .......................................37, 53
INDF....................................................................................43
Instruction Set Summary.....................................................55
INT Interrupt........................................................................49
INTCON ............................................................17, 43, 48, 49
INTEDG ..............................................................................49
Interrupts
Flag ............................................................................. 48
Interrupt on Change Feature....................................... 23
S
Saving W Register and STATUS in RAM........................... 50
SLEEP .................................................................... 37, 42, 52
Software Simulator (MPSIM) .............................................. 69
Special Features of the CPU .............................................. 37
Special Function Registers................................................. 12
Stack................................................................................... 18
DS30430B-page 115
PIC16F8X
Overflows .................................................................... 18
Underflows .................................................................. 18
STATUS ....................................................................7, 15, 43
T
Time-out ..............................................................................43
Timer0
Switching Prescaler Assignment................................. 31
T0IF............................................................................. 49
Timer0 Module ............................................................ 27
TMR0 Interrupt............................................................ 49
TMR0 with External Clock........................................... 29
Timing Diagrams
Time-out Sequence..................................................... 45
Timing Diagrams and Specifications.............................78, 92
TRISA..................................................................................21
TRISB............................................................................23, 43
LIST OF EXAMPLES
Example 3-1: Instruction Pipeline Flow .............................. 10
Example 4-1: Indirect Addressing ...................................... 19
Example 4-2: How to Clear RAM Using Indirect
Addressing ................................................... 19
Example 5-1: Initializing PORTA ........................................ 21
Example 5-2: Initializing PORTB ........................................ 24
Example 5-3: Read-Modify-Write Instructions
on an I/O Port............................................... 25
Example 6-1: Changing Prescaler (Timer0→WDT) ........... 31
Example 6-2: Changing Prescaler (WDT→Timer0) ........... 31
Example 7-1: Data EEPROM Read ................................... 34
Example 7-2: Data EEPROM Write ................................... 34
Example 7-3: Write Verify .................................................. 35
Example 8-1: Saving STATUS and W Registers
in RAM ...................................................... 50
W
LIST OF FIGURES
W.........................................................................................43
Wake-up from SLEEP ...................................................43, 52
Watchdog Timer (WDT) ....................................37, 42, 43, 51
WDT ....................................................................................43
Period.......................................................................... 51
Programming Considerations ..................................... 51
Time-out...................................................................... 43
Figure 3-1:
Figure 3-2:
Figure 4-1:
X
XT..................................................................................39, 47
Z
Zero bit ..................................................................................7
DS30430B-page 116
PIC16F8X Block Diagram .............................. 8
Clock/Instruction Cycle ................................ 10
Program Memory Map and Stack PIC16F83/CR83........................................... 11
Figure 4-2: Program Memory Map and Stack PIC16F84/CR84........................................... 11
Figure 4-3: Register File Map - PIC16F83/CR83 ........... 13
Figure 4-4: Register File Map - PIC16F84/CR84 ........... 13
Figure 4-5: STATUS Register (Address 03h, 83h) ......... 15
Figure 4-6: OPTION Register (Address 81h) ................. 16
Figure 4-7: INTCON Register (Address 0Bh, 8Bh) ........ 17
Figure 4-8: Loading of PC in Different Situations ........... 18
Figure 4-9: Direct/Indirect Addressing ............................ 19
Figure 5-1: Block Diagram of Pins RA3:RA0.................. 21
Figure 5-2: Block Diagram of Pin RA4 ........................... 21
Figure 5-3: Block Diagram of Pins RB7:RB4.................. 23
Figure 5-4: Block Diagram of Pins RB3:RB0.................. 23
Figure 5-5: Successive I/O Operation ............................ 25
Figure 6-1: TMR0 Block Diagram ................................... 27
Figure 6-2: TMR0 Timing: Internal Clock/
No Prescaler ................................................ 27
Figure 6-3: TMR0 Timing: Internal Clock/
Prescale 1:2 ................................................. 28
Figure 6-4: TMR0 Interrupt Timing ................................. 28
Figure 6-5: Timer0 Timing With External Clock.............. 29
Figure 6-6: Block Diagram of the TMR0/WDT
Prescaler ...................................................... 30
Figure 7-1: EECON1 Register (Address 88h) ................ 33
Figure 8-1: Configuration Word - PIC16CR83
and PIC16CR84 ........................................... 38
Figure 8-2: Configuration Word - PIC16F83
and PIC16F84.............................................. 38
Figure 8-3: Crystal/Ceramic Resonator Operation
(HS, XT or LP OSC Configuration) .............. 39
Figure 8-4: External Clock Input Operation
(HS, XT or LP OSC Configuration) .............. 39
Figure 8-5: External Parallel Resonant Crystal
Oscillator Circuit ........................................... 40
Figure 8-6: External Series Resonant Crystal
Oscillator Circuit ........................................... 40
Figure 8-7: RC Oscillator Mode ...................................... 41
Figure 8-8: Simplified Block Diagram of
On-Chip Reset Circuit .................................. 42
Figure 8-9: External Power-on Reset Circuit
(For Slow VDD Power-up)............................. 44
Figure 8-10: Time-out Sequence on Power-up
(MCLR not Tied to VDD): Case 1.................. 45
PIC16F8X
(MCLR Not Tied To VDD): Case 2 ................ 45
(MCLR Tied to VDD): Fast VDD
Rise Time ..................................................... 46
Figure 8-13: Time-Out Sequence on Power-Up
(MCLR Tied to VDD): Slow VDD
Rise Time ..................................................... 46
Figure 8-14: Brown-out Protection Circuit 1...................... 47
Figure 8-15: Brown-out Protection Circuit 2...................... 47
Figure 8-16: Interrupt Logic .............................................. 48
Figure 8-17: INT Pin Interrupt Timing ............................... 49
Figure 8-18: Watchdog Timer Block Diagram................... 51
Figure 8-19: Wake-up From Sleep Through
Interrupt ........................................................ 52
Figure 8-20: Typical In-system Serial Programming
Connection ................................................... 53
Figure 9-1: General Format for Instructions.................... 55
Figure 11-1: Parameter Measurement Information........... 77
Figure 11-2: Load Conditions ........................................... 77
Figure 11-3: External Clock Timing .................................. 78
Figure 11-4: CLKOUT and I/O Timing .............................. 79
Figure 11-5: Reset, Watchdog Timer,
Oscillator Start-up Timer and
Power-up Timer Timing ................................ 80
Figure 11-6: Timer0 Clock Timings................................... 81
Figure 13-1: Parameter Measurement Information........... 91
Figure 13-2: Load Conditions ........................................... 91
Figure 13-3: External Clock Timing .................................. 92
Figure 13-4: CLKOUT and I/O Timing .............................. 93
Figure 13-5: Reset, Watchdog Timer,
Power-up Timer Timing ................................ 94
Figure 13-6: Timer0 Clock Timings................................... 95
Table 11-3:
Table 11-4:
Table 11-5:
Table 11-6:
Table 13-1:
Table 13-2:
Table 13-3:
Table 13-4:
Table 13-5:
Table 13-6:
External Clock Timing Requirements............78
CLKOUT and I/O Timing Requirements ...... 79
Reset, Watchdog Timer,
Power-up Timer Requirements ....................80
Timer0 Clock Requirements .........................81
Cross Reference of Device Specs for
Oscillator Configurations and Frequencies
of Operation (Commercial Devices)..............86
Timing Parameter Symbology.......................91
External Clock Timing Requirements............92
CLKOUT and I/O Timing Requirements .......93
Reset, Watchdog Timer,
Power-up Timer Requirements .....................94
Timer0 Clock Requirements .........................95
LIST OF TABLES
Table 1-1:
Table 3-1:
Table 4-1:
Table 5-1:
Table 5-2:
Table 5-3:
Table 5-4:
Table 6-1:
Table 7-1:
Table 8-1:
Table 8-2:
Table 8-3:
Table 8-4:
Table 8-5:
Table 8-6:
Table 8-7:
Table 9-1:
Table 9-2:
Table 10-1:
Table 11-1:
Table 11-2:
PIC16F8X Family of Devices ......................... 4
PIC16F8X Pinout Description......................... 9
Register File Summary................................. 14
PORTA Functions ........................................ 22
Summary of Registers Associated
With PORTA................................................. 22
PORTB Functions ........................................ 24
With PORTB................................................. 24
Registers Associated with Timer0 ................ 31
Registers/Bits Associated with
Data EEPROM ............................................ 35
PIC16F83/CR83/F84/CR84 Capacitor
Selection for Ceramic Resonators................ 39
PIC16F83/CR83/F84/CR84 Capacitor
Selection for Crystal Oscillator ..................... 40
Reset Condition for Program Counter
and the STATUS Register............................ 43
Reset Conditions for All Registers................ 43
Time-out in Various Situations ..................... 47
STATUS bits and Their Significance ............ 47
With the Watchdog Timer............................. 51
OPCODE Field Descriptions ........................ 55
Instruction Set Summary .............................. 56
Development Tools from Microchip.............. 70
Cross Reference of Device Specs for
Oscillator Configurations and Frequencies
of Operation (Commercial Devices) ............ 72
Timing Parameter Symbology ...................... 77
DS30430B-page 117
PIC16F8X
NOTES:
DS30430B-page 118
PIC16F8X
ON-LINE SUPPORT
Microchip provides two methods of on-line support.
These are the Microchip BBS and the Microchip World
Wide Web (WWW) site.
Use Microchip's Bulletin Board Service (BBS) to get
current information and help about Microchip products.
Microchip provides the BBS communication channel for
you to use in extending your technical staff with microcontroller and memory experts.
To provide you with the most responsive service possible,
the Microchip systems team monitors the BBS, posts
the latest component data and software tool updates,
provides technical help and embedded systems
insights, and discusses how Microchip products provide project solutions.
The web site, like the BBS, is used by Microchip as a
means to make files and information easily available to
customers. To view the site, the user must have access
to the Internet and a web browser, such as Netscape or
Microsoft Explorer. Files are also available for FTP
download from our FTP site.
Connecting to the Microchip Internet Web Site
The Microchip web site is available by using your
favorite Internet browser to attach to:
www.microchip.com
The file transfer site is available by using an FTP service to connect to:
ftp.mchip.com/biz/mchip
The web site and file transfer site provide a variety of
services. Users may download files for the latest
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available for consideration is:
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Questions
• Design Tips
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• Job Postings
• Microchip Consultant Program Member Listing
• Links to other useful web sites related to
Microchip Products
The procedure to connect will vary slightly from country
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agent for details if you have a problem. CompuServe
service allow multiple users various baud rates
depending on the local point of access.
The following connect procedure applies in most locations.
1. Set your modem to 8-bit, No parity, and One stop
(8N1). This is not the normal CompuServe setting
which is 7E1.
2. Dial your local CompuServe access number.
3. Depress the <Enter> key and a garbage string will
appear because CompuServe is expecting a 7E1
setting.
4. Type +, depress the <Enter> key and “Host Name:”
will appear.
5. Type MCHIPBBS, depress the <Enter> key and you
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In the United States, to find the CompuServe phone
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(800) 848-4480 for 300-2400 baud or (800) 331-7166
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For voice information (or calling from overseas), you
may call (614) 723-1550 for your local CompuServe
number.
Microchip regularly uses the Microchip BBS to distribute
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Systems Information and Upgrade Hot Line
The Systems Information and Upgrade Line provides
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1-602-786-7302 for the rest of the world.
960513
Connecting to the Microchip BBS
Connect worldwide to the Microchip BBS using either
the Internet or the CompuServe communications network.
Internet:
You can telnet or ftp to the Microchip BBS at the
address:
mchipbbs.microchip.com
CompuServe Communications Network:
When using the BBS via the Compuserve Network,
in most cases, a local call is your only expense.
The Microchip BBS connection does not use CompuServe
membership services, therefore you do not need
CompuServe membership to join Microchip's BBS.
There is no charge for connecting to the Microchip BBS.
Trademarks: The Microchip name, logo, PIC, PICSTART,
PICMASTER and PRO MATE are registered trademarks
of Microchip Technology Incorporated in the U.S.A. and
other countries. FlexROM, MPLAB and fuzzyLAB, are
trademarks and SQTP is a service mark of Microchip in
the U.S.A.
fuzzyTECH is a registered trademark of Inform Software
Corporation. IBM, IBM PC-AT are registered trademarks
of International Business Machines Corp. Pentium is a
trademark of Intel Corporation. Windows is a trademark
and MS-DOS, Microsoft Windows are registered trademarks of Microsoft Corporation. CompuServe is a registered trademark of CompuServe Incorporated.
All other trademarks mentioned herein are the property of
their respective companies.
DS30430B-page 119
PIC16F8X
READER RESPONSE
It is our intention to provide you with the best documentation possible to ensure successful use of your Microchip product. If you wish to provide your comments on organization, clarity, subject matter, and ways in which our documentation
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Please list the following information, and use this outline to provide us with your comments about this Data Sheet.
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Literature Number: DS30430B
Questions:
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DS30430B-page 120
PIC16F8X
PIC16F8X PRODUCT IDENTIFICATION SYSTEM
To order or obtain information, e.g., on pricing or delivery, refer to the factory or the listed sales office.
PART NO.
Device
X
-XX
Frequency Temperature
Range
Range
/XX
XXX
Package
Pattern
Device
PIC16F8X(2), PIC16F8XT(3)
PIC16LF8X(2), PIC16LF8XT(3)
PIC16CR8X(2), PIC16CR8XT(3)
PIC16LCR8X(2), PIC16LCR8XT(3)
Frequency
Range
04
10
= 4 MHz
= 10 MHz
Temperature
Range
b(1)
I
= 0°C to
= -40°C to
Package
P
SO
= PDIP
= SOIC (Gull Wing, 300 mil body)
Pattern
3-digit Pattern Code for QTP, ROM (blank otherwise)
+70°C
+85°C
(Commercial)
(Industrial)
Examples:
a)
b)
c)
PIC16F84 -04/P 301 = Commercial
temp., PDIP package, 4 MHz, normal
VDD limits, QTP pattern #301.
PIC16LF84 - 04I/SO = Industrial temp.,
SOIC package, 200 kHz, Extended VDD
limits.
PIC16CR84 - 10I/P = ROM program
memory, Industrial temp., PDIP package,
10MHz, normal VDD limits.
Note 1: b = blank
2: F
= Standard VDD range
LF = Extended VDD range
CR = ROM Version, Standard VDD
range
LCR = ROM Version, Extended VDD
range
3: T = in tape and reel - SOIC, SSOP
packages only.
Sales and Support
Data Sheets
Products supported by a preliminary Data Sheet may have an errata sheet describing minor operational differences and recommended workarounds. To determine if an errata sheet exists for a particular device, please contact one of the following:
1. Your local Microchip sales office (see last page)
2. The Microchip Corporate Literature Center U.S. FAX: (602) 786-7277
3. The Microchip’s Bulletin Board, via your local CompuServe number (CompuServe membership NOT required).
Please specify which device, revision of silicon and Data Sheet (include Literature #) you are using.
Development Tools
For the latest version information and upgrade kits for Microchip Development Tools, please call 1-800-755-2345 or 1-602-786-7302.
The latest version of Development Tools software can be downloaded from either our Bulletin Board or Worldwide Web Site. (Information on how to connect to our BBS or WWW site can be found in the On-Line Support section of this data sheet.)
DS30430B-page 121
WORLDWIDE SALES & SERVICE
AMERICAS
ASIA/PACIFIC
EUROPE
Corporate Office
Microchip Technology Inc.
2355 West Chandler Blvd.
Chandler, AZ 85224-6199
Tel: 602 786-7200 Fax: 602 786-7277
Technical Support: 602 786-7627
Web: http://www.microchip.com
Atlanta
500 Sugar Mill Road, Suite 200B
Atlanta, GA 30350
Tel: 770 640-0034 Fax: 770 640-0307
Boston
5 Mount Royal Avenue
Marlborough, MA 01752
Tel: 508 480-9990 Fax: 508 480-8575
Chicago
333 Pierce Road, Suite 180
Itasca, IL 60143
Tel: 708 285-0071 Fax: 708 285-0075
Dallas
14651 Dallas Parkway, Suite 816
Dallas, TX 75240-8809
Tel: 972 991-7177 Fax: 972 991-8588
Dayton
Suite 150
Two Prestige Place
Miamisburg, OH 45342
Tel: 513 291-1654 Fax: 513 291-9175
Los Angeles
18201 Von Karman, Suite 1090
Irvine, CA 92612
Tel: 714 263-1888 Fax: 714 263-1338
New York
Microchip Technmgy Inc.
150 Motor Parkway, Suite 416
Hauppauge, NY 11788
Tel: 516 273-5305 Fax: 516 273-5335
San Jose
2107 North First Street, Suite 590
San Jose, CA 95131
Tel: 408 436-7950 Fax: 408 436-7955
Toronto
5925 Airport Road, Suite 200
Mississauga, Ontario L4V 1W1, Canada
Tel: 905 405-6279 Fax: 905 405-6253
Hong Kong
Microchip Technology
RM 3801B, Tower Two
Metroplaza
223 Hing Fong Road
Kwai Fong, N.T. Hong Kong
Tel: 852 2 401 1200 Fax: 852 2 401 3431
India
No. 6, Legacy, Convent Road
Bangalore 560 025 India
Tel: 91 80 526 3148 Fax: 91 80 559 9840
Korea
168-1, Youngbo Bldg. 3 Floor
Samsung-Dong, Kangnam-Ku,
Seoul, Korea
Tel: 82 2 554 7200 Fax: 82 2 558 5934
Shanghai
Unit 406 of Shanghai Golden Bridge Bldg.
2077 Yan’an Road West, Hongiao District
Shanghai, Peoples Republic of China
Tel: 86 21 6275 5700
Fax: 86 21 6275 5060
Singapore
200 Middle Road
#10-03 Prime Centre
Singapore 188980
Tel: 65 334 8870 Fax: 65 334 8850
Taiwan, R.O.C
10F-1C 207
Tung Hua North Road
Taipei, Taiwan, ROC
Tel: 886 2 717 7175 Fax: 886 2 545 0139
United Kingdom
Arizona Microchip Technology Ltd.
Unit 6, The Courtyard
Meadow Bank, Furlong Road
Bourne End, Buckinghamshire SL8 5AJ
Tel: 44 1628 850303 Fax: 44 1628 850178
France
Arizona Microchip Technology SARL
Zone Industrielle de la Bonde
2 Rue du Buisson aux Fraises
91300 Massy - France
Tel: 33 1 69 53 63 20 Fax: 33 1 69 30 90 79
Germany
Arizona Microchip Technology GmbH
Gustav-Heinemann-Ring 125
D-81739 Muenchen, Germany
Tel: 49 89 627 144 0 Fax: 49 89 627 144 44
Italy
Arizona Microchip Technology SRL
Centro Direzionale Colleone Pas Taurus 1
Viale Colleoni 1
20041 Agrate Brianza
Milan Italy
Tel: 39 39 6899939 Fax: 39 39 689 9883
JAPAN
Microchip Technology Intl. Inc.
Benex S-1 6F
3-18-20, Shin Yokohama
Kohoku-Ku, Yokohama
Kanagawa 222 Japan
Tel: 81 45 471 6166 Fax: 81 45 471 6122
9/3/96
All rights reserved.  1996, Microchip Technology Incorporated, USA.
Information contained in this publication regarding device applications and the like is intended through suggestion only and may be superseded by updates. No representation or warranty is given and no liability is assumed by Microchip Technology Incorporated with respect to the accuracy or use of such information, or infringement
of patents or other intellectual property rights arising from such use or otherwise. Use of Microchip’s products as critical components in life support systems is not authorized except with express written approval by Microchip. No licenses are conveyed, implicitly or otherwise, under any intellectual property rights. The Microchip logo and
name are registered trademarks of Microchip Technology Inc. All rights reserved. All other trademarks mentioned herein are the property of their respective companies.
DS30430B - page 122

Universidad Tecnológica de Querétaro

Transcription

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