Hello there!

I need help regarding my project. I have designed the Hardware completely. I am designing a path learning car.

However i am having trouble with the code. I am using PIC16F877 mc. the code is attached.

MY PROBLEMS: When i am trying to send an interrupt to pin RB0 then no pulse is detected. which means no interrupt. I want to know the problem. Can anyone help me?

        list      p=16f877            ; list directive to define processor
        #include <p16f877.inc>        ; processor specific variable definitions
        
        __CONFIG _CP_OFF & _WDT_OFF & _BODEN_ON & _PWRTE_ON & _XT_OSC & _WRT_ENABLE_ON & _LVP_ON & _DEBUG_OFF & _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
    
CHECK EQU 0X20
TEMP EQU 0X21
A1 EQU 0X022
B1 EQU 0X023
C1 EQU 0X024
    
    
    
    
    
    ;**********************************************************************
    ORG     0x000             ; processor reset vector
    clrf    PCLATH            ; ensure page bits are cleared
    GOTO    MAIN              ; go to beginning of program
    
    
    ORG     0x004             ; interrupt vector location
    MOVF CHECK,0
    XORLW D'1'
    MOVWF CHECK
    
    MOVLW b'10000000'
    MOVWF PORTD
    ; clearing in software
    BCF INTCON,1;
    RETFIE
    
    
    
    
MAIN
    

    MOVLW B'10100101';
    MOVWF TEMP;
    MOVLW D'1';
    MOVWF CHECK;

    
    ;;;;;;;;;;;;;;;PORTS
    BANKSEL TRISC
    MOVLW B'00000000'
    MOVWF TRISC
    
    BANKSEL TRISB
    
    MOVLW B'11111111'
    MOVWF TRISB

    
    BANKSEL INTCON
    
    
    ;;;On Interrupts
    BCF INTCON,1;
    BSF INTCON,4;
    BSF INTCON, 6;
    BSF INTCON, 7;
    BSF INTCON, 3;
    ;; stop the car

LOOP
    ;;;;;;;;;;;;;;;;;;;;;;
    MOVF CHECK,0
    XORLW D'1'
    BTFSS STATUS,Z;
    GOTO LOOP1
    
    
;; START CAR ( any pin on port C)
    MOVLW B'11111111'
    MOVWF PORTC;
;    CALL DELAY1

    GOTO LOOP
    
LOOP1
    
    MOVF CHECK,0
    XORLW D'1'
    BTFSC STATUS,Z;
    GOTO LOOP

    BANKSEL PORTC
    MOVLW B'00000000'
    MOVWF PORTC;
    GOTO LOOP1
    ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
 
    END

 

You need a bit of code around the interrupt to save and restore STATUS and W.
You can find it in the F877 file in here:

http://ww1.microchip.com/downloads/en/DeviceDoc/code.zip

That may not fix the problem but it is a start.

 

post the circuit also, so we know how you have things wired up and connected, since I see you have Low voltage Programming enabled and all......depending on how you have this connected in the circuit, the pic may not even start up at all....


B. Morse

 

post the circuit also, so we know how you have things wired up and connected, since I see you have Low voltage Programming enabled and all......depending on how you have this connected in the circuit, the pic may not even start up at all....


B. Morse

No the PIC has started. Because the code which is burnt default by myself works fine. But when i give interrupt then its not working.
However my code works properly in PROTEUS but not working on Hardware..

 

No the PIC has started. Because the code which is burnt default by myself works fine. But when i give interrupt then its not working.
However my code works properly in PROTEUS but not working on Hardware..

How did you determine the PIC starts fine? Do you have another routine that test something to determine that? Simulating circuits to me is like making a lot of assumptions ( that are usually wrong).... better to have built the circuit on a breadboard than to simulate it....

B. Morse

 

How did you determine the PIC starts fine? Do you have another routine that test something to determine that? Simulating circuits to me is like making a lot of assumptions ( that are usually wrong).... better to have built the circuit on a breadboard than to simulate it....

B. Morse

Yeah i have worked on breadboard. The PIC is working fine on the HARDWARE. i have check it with other sample codes. And also in the given code the initial output of "binary 1s" is coming.

 

Can you use actual bit names in operands (for INTCON for example) or perhaps add a comment or two? We shouldn't have to do this for you since you're the one asking for help.

If you are using interrupts then your interrupt handler is deficient...

Regards, Mike