1.- Conocer el lenguaje ensamblador así como las herramientas básicas para programar el microcontrolador PIC16F877A.

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; File Version: *

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; Author: *

; Company: *

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;**********************************************************************

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; Files Required: P16F877A.INC *

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; Notes: *

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list p=16f877A ; list directive to define processor

#include ; processor specific variable definitions

__CONFIG _CP_OFF & _WDT_OFF & _BODEN_OFF & _PWRTE_ON & _XT_OSC & _WRT_OFF & _LVP_ON & _CPD_OFF

; '__CONFIG' directive is used to embed configuration data within .asm file.

; The lables following the directive are located in the respective .inc file.

; See respective data sheet for additional information on configuration word.

;***** VARIABLE DEFINITIONS

w_temp EQU 0x7D ; variable used for context saving

status_temp EQU 0x7E ; variable used for context saving

pclath_temp EQU 0x7F ; variable used for context saving

CounterA EQU 0x7A ;memoria donde lo guarda

CounterB EQU 0x7B ;memoria donde lo guarda

CounterC EQU 0x7C ;memoria donde lo guarda

;**********************************************************************

ORG 0x000 ; processor reset vector

nop ; nop required for icd

goto main ; go to beginning of program

ORG 0x004 ; interrupt vector location

movwf w_temp ; save off current W register contents

movf STATUS,w ; move status register into W register

movwf status_temp ; save off contents of STATUS register

movf PCLATH,w ; move pclath register into w register

movwf pclath_temp ; save off contents of PCLATH register

; isr code can go here or be located as a call subroutine elsewhere

movf pclath_temp,w ; retrieve copy of PCLATH register

movwf PCLATH ; restore pre-isr PCLATH register contents

movf status_temp,w ; retrieve copy of STATUS register

movwf STATUS ; restore pre-isr STATUS register contents

swapf w_temp,f

swapf w_temp,w ; restore pre-isr W register contents

retfie ; return from interrupt

main

;Configuracion de puertos

movlw 20H ;cambiamos al banco 1

movwf STATUS ;configurando el puerto como salida

movlw 00H ; ucf status ,5 asi se puede poner

movwf TRISB ; bcf status, asi se puede poner

bsf TRISA,0 ;poner el puerto a en 0

movlw 00H

movwf STATUS

inicio

btfsc PORTA,0

goto modo1

goto modo2

modo1

BSF PORTB,0

CALL DELAY2S

BCF PORTB,0

CALL DELAY2S

CALL DELAY2S

GOTO inicio

modo2

BSF PORTB,0

CALL DELAY1S

BCF PORTB,0

CALL DELAY1S

CALL DELAY1S

GOTO inicio

; remaining code goes here

DELAY2S

;PIC Time Delay = 2,00000200 s with Osc = 4000000 Hz

movlw D'11'

movwf CounterC

movlw D'38'

movwf CounterB

movlw D'93'

movwf CounterA

loop2 decfsz CounterA,1

goto loop2

decfsz CounterB,1

goto loop2

decfsz CounterC,1

goto loop2

retlw 0

DELAY1S

;PIC Time Delay = 0.10000200 s with Osc = 4000000 Hz

movlw D'130'

movwf CounterB

movlw