CODEWITHSUNDEEP
assemblyinterruptpicmicrochipmplab
Christronics
Christronics

Reputation: 1

How to make PIC18F4520 launch RTC interrupt from datasheet

I want to build a binary clock using the timer1 module as RTC with the code example from the datasheet, but although I wrote the necessary code around it, the interrupt does not trigger. Did I miss a register setting or memory address? I'm new to PIC programming but got some experience in assembly.

        UDATA_ACS
secs    RES 1
mins    RES 1
hours   RES 1

ORG 0x0000            ; processor reset vector
    GOTO    MAIN                   ; go to beginning of program
ORG 0x0800
    BTFSC   intcon,int0if
    CALL int0_isr
    RETFIE

MAIN_PROG CODE                      ; let linker place main program
ORG 0x0100
MAIN
    MOVLW  080h        ; Preload TMR1 register pair
    MOVWF  TMR1H       ; for 1 second overflow
    CLRF   TMR1L
    MOVLW  b'00001101' ; Configure for external clock,
    MOVWF  T1CON       ; Asynchronous operation, external oscillator
    CLRF   secs        ; Initialize timekeeping registers
    CLRF   mins        ;
    MOVLW  .12
    MOVWF  hours
    BCF    intcon,int0if
    BSF    INTCON,INT0IE
    BCF    INTCON2,INTEDG0
;    BSF  rcon,ipen
;    BSF  intcon,peie
    BSF    PIE1, TMR1IE ; Enable Timer1 interrupt
    BSF    intcon,gie

    clrf    lata
    movlw   0x0f
    movwf   adcon1
    movwf   0x07
    movwf   cmcon
    movlw   0x00
    movwf   trisa
    clrf    portb
    movlw   0x00
    movwf   trisb
    clrf    latd
    movlw   0x00
    movwf   trisd

    movlw   secs
    movwf   lata
    movlw   mins
    movwf   latb
    movlw   hours
    movwf   latd
here
    goto    here

    RETURN

int0_isr 
    ;from datasheet p.133
    RETFIE
~~~~~~~~~

Upvotes: 0

Views: 132

Answers (1)

Mike
Mike

Reputation: 4288

You are using the wrong interrupt vector with 0800.
Interrupt Vector high: 0008h
Interrupt Vector low: 0018h 

ORG 0x0008
    BTFSC   intcon,int0if
    CALL int0_isr
    RETFIE

Upvotes: 1

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