Assembly Language - My program keeps on restarting - Electronic Circuits Projects Diagrams Free

avinsinanan · 14th April 2005, 02:56 PM

Hello,

I wrote some code and becasue of the four lines with the asterisks (*), my program keeps on restarting ( It keeps on going back to the line ORG )x00, nop ).

Without the four lines it gives a one second delay. Why does it keep restarting with the four lines?

INCLUDE <P16f877.inc>
LIST P=16F877

count EQU 0x26
five EQU 0x27

ORG 0x00
nop
goto main
ORG 0x10

main
BANKSEL OPTION_REG *
movlw B'00100001' ;*enable counter mode, 1:4 prescaler
movwf OPTION_REG ;*increment on rising edge
BANKSEL TMR0*
movlw D'250'
movwf count
movlw 0x10
movwf five

point decfsz five
goto start
goto here2
start movlw D'249'
here addlw 0xFF
btfss STATUS,Z
goto here
decfsz count
goto start
goto point

here2 movf TMR0,W
clrf TMR0
movwf PORTD

stop sleep
END

Yours Respectfully
Avin Sinanan

Exo · 14th April 2005, 03:09 PM

did you disable your watchdog timer ?

bonxer · 14th April 2005, 05:20 PM

Yes, it is the watchdog timer, and if the prescaler for the timer is done incorrectly, the watchdog can bite even if turned off. Make sure your WDT is turned off in your fuse settings. Then, in the section that you have starred, you must issue a clear watchdog timer command before assigning the prescaler.

pike · 15th April 2005, 04:23 AM

OMG this problem got me so many times you wouldn't believe how frustrating it was :x :evil: . Almost quit electronics altogther!!

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14th April 2005, 02:56 PM	(permalink)
avinsinanan	Assembly Language - My program keeps on restarting Hello, I wrote some code and becasue of the four lines with the asterisks (), my program keeps on restarting ( It keeps on going back to the line ORG )x00, nop ). Without the four lines it gives a one second delay. Why does it keep restarting with the four lines? INCLUDE <P16f877.inc> LIST P=16F877 count EQU 0x26 five EQU 0x27 ORG 0x00 nop goto main ORG 0x10 main BANKSEL OPTION_REG movlw B'00100001' ;enable counter mode, 1:4 prescaler movwf OPTION_REG ;increment on rising edge BANKSEL TMR0* movlw D'250' movwf count movlw 0x10 movwf five point decfsz five goto start goto here2 start movlw D'249' here addlw 0xFF btfss STATUS,Z goto here decfsz count goto start goto point here2 movf TMR0,W clrf TMR0 movwf PORTD stop sleep END Yours Respectfully Avin Sinanan __________________ Yours Respectfully Avin Sinanan

14th April 2005, 03:09 PM	(permalink)
Exo	did you disable your watchdog timer ?

14th April 2005, 05:20 PM	(permalink)
bonxer	Yes, it is the watchdog timer, and if the prescaler for the timer is done incorrectly, the watchdog can bite even if turned off. Make sure your WDT is turned off in your fuse settings. Then, in the section that you have starred, you must issue a clear watchdog timer command before assigning the prescaler. __________________ There\'s no graphic in my signature. I don\'t know your IP, and I\'m not trying to hax0r you. You\'re welcome.

15th April 2005, 04:23 AM	(permalink)
pike	OMG this problem got me so many times you wouldn't believe how frustrating it was :x :evil: . Almost quit electronics altogther!! __________________ www.winpicprog.co.uk - Great PIC language tutorials.