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Help me fix coding for PIC16C745 which will turn on/off a LED light

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christina86

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Dear Friends,

I am using the MPLab 7.2 to write an assembly language using PIC16C745 to turn ON & OFF the Led Light using the push button.

I have successfully burn the Code inside the PIC16C 745 but when i apply the 5V voltage .it failed to turn on.
Here is my code :


list p=16c745 ; list directive to define processor
#include <p16c745.inc> ; processor specific variable definitions

__CONFIG _H4_OSC&_WDT_OFF&_PWRTE_OFF&_CP_OFF




org 0X00000030

Start
bsf STATUS,RP0 ; select bank1
movlw b'00000110' ; Set pins PORTB 1,2 as Input and the rest as "output"
movwf TRISB ;
bcf STATUS, RP0 ; go back to Bank 0


ON
btfsc PORTB,1 ; has S1 been press? (Normally high,goes low when pressed.)
goto ON ; No, go back check again
bsf PORTB,0

OFF
btfsc PORTB,2 ; Has key been press? (Normally high, goes low when pressed.)
goto OFF ; No, check again
bcf PORTB,0

goto Start
end ; directive indicates end of code

Can you help me to check where did i go wrong and how the correct way should be ?
 

Re: Help for 16C745

ur code looks strange...

here is program for ON/OFF of the LED using Interrupts on PIC16F84A, i think you can easily transfer this program to your chip:

Code: 
;===================================================== 
; File: RB0Int.ASM 
; Date: April 22, 2006 
; Author: Julio Sanchez 
; Processor: 16F84A 
;===================================================== 
; Description: 
; Program to test interrupt on port RB0 
; A pushbutton switch is connected to port RB0. 
; The pushbutton toggles a LED on port-B, line 7 
; 
; 
;===================================================== 

;========================= 
; setup and configuration 
;========================= 
processor 16f84A 
include <p16f84A.inc> 
__config _XT_OSC & _WDT_OFF & _PWRTE_ON & _CP_OFF 

;===================================================== 
; variables in PIC RAM 
;===================================================== 

cblock 0x0d       ; Start of block 
count2               ; ISR counter 
old_w                 ; Context saving 
old_STATUS                 
Delay1          
count1 
endc 


;======================================================== 
; ********** PROGRAM START ********** 
;======================================================== 
org 0                   ; Program start at address 0 
goto main 

;============================= 
; INTERRUPT HANDLER 
;============================= 
org 0x04 
goto IntServ 

;============================= 
; MAIN PROGRAM 
;============================= 
main: 
bsf      STATUS,RP0         ; Select Bank1 
bcf      OPTION_REG,INTEDG   ; Set interrupt on falling edge    
                     ; by clearing INTEDG bit of OPTION_REG    

movlw    b'00000001'         ; PORTB bit 0 
movwf   TRISB            ; is Input, all other bits are Output 

bcf      STATUS,RP0          ; Go back to Bank0    


clrf    PORTB             ; Clear PORTB 
;bsf    PORTB,0          ; set PORTB bit 0 

                     ; SETUP INTERRUPTS 
bcf INTCON,INTF          ; Clear external interrupt flag (INTF = bit 1) 
bsf INTCON,GIE             ; Enable global interrupts (GIE = bit 7) 
bsf INTCON,INTE          ; Enable RB0 interrupt (INTE = bit 4) 

;============================ 
; flash led 
;============================ 
Loop: 

nop 
nop 
nop 
goto   Loop 
;clrf   PORTB 


;======================================================= 
; Interrupt Service Routine 
;======================================================= 

IntServ:               ; First test if source is an RB0 interrupt 
btfss INTCON,INTF          ; INTF flag is RB0 interrupt 
goto notRB0             ; Go if not RB0 origin 

                     ; Save context 
movwf old_w             ; Save w register 
swapf STATUS,w            ; STATUS to w 
movwf old_STATUS          ; Save STATUS 
                     ; Make sure that interrupt occurred on the falling edge 
                     ; of the signal. If not, abort handler 
btfsc PORTB,0             ; Is bit set? 
goto exitISR             ; Go if clear 

;========================= 
; interrupt action 
;========================= 
;clrf   PORTB 
movlw 10                ; Number of repetitions 
movwf count2             ; To counter 
wait:                  ; Check to see that port-B bit 0 is still 0 
                     ; If not, wait until it changes 
btfsc PORTB,0             ; Is bit set? 
goto exitISR             ; Go if bit not 0 
                     ; At this point RB0 bit is clear 
decfsz count2,f          ; Count this iteration 
goto wait                ; Continue if not zero 
                     ; Interrupt action consists of toggling bit 2 of 
                     ; port-B to turn LED on and off 
; ACTION!!!! 

movlw b'10000000'          ; Xoring with a 1-bit produces 
                  ; the complement 
xorwf   PORTB,1             ; Complement bit 2, port-B 

;========================= 
; exit ISR 
;========================= 
exitISR:               ; Restore context 

swapf old_STATUS,w          ; Saved STATUS to w 
swapf old_w,f             ; Swap file register in itself 
swapf old_w,w             ; re-swap back to w 

notRB0:                  ; Reset,interrupt 
bcf INTCON,INTF          ; Clear INTCON bit 1 
retfie 

delay: 
movlw 4 
movwf count1 ; Store value in counter 
repeat: 
decfsz count1,f ; Decrement counter 
goto repeat ; Continue if not 0 
return 

end
 

Re: Help for 16C745

hi,

Thank you so much to post the sample code. Your code only used one switch is it ?
May i know how to schematic be like. May you help me to ponit out where did i go wrong in my code.

Thank you
 

Help for 16C745

it is using active Low logic, take a value of 4.7K for the resistor.
well...ur code is mess, and it doesnt use interrupts, so forget it :D
use interrupts for such things :)
 

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