Hello All,

I've run into some problems while trying to implement a simple delay-routing on my DS89C450. After having peeked into various application notes and having tried out the code therein with no immediate success, I ventured on to my current, rather simple approach.
Below you will find my source code - I hope I am not offending anyone by posting it in the message - and the problematic part is that when it is flashed into the micro, the if-statements determining the current time and incrementing seconds, minutes and hours are left untouched, whereas in the simulator they work.

/Thomas

#include <REG420.H>

char timer0_tick;
int secs,mins,hrs;

void timer0_isr(void) interrupt 1
{
timer0_tick++;
P1 ^= 0x80;

return;
}

void timer0_initialize(void)
{
EA = 0; /* disable interrupts */
TMOD = (TMOD & 0xF0) | 0x01; /* Set T/C0 Mode */
CKCON = (CKCON & ~0x03); /* Select external oscillator as source */
CKMOD = (CKMOD & ~0x03); /* Select external oscillator as source */
TMOD = (TMOD & ~0x02); /* Select external oscillator as source */
ET0 = 1; /* Enable Timer 0 Interrupts */
TR0 = 1; /* Start Timer 0 Running */
EA = 1; /* enable interrupts */

return;
}

void init(void)
{
timer0_tick = 0;
timer0_initialize();

secs, mins, hrs = 0;
P0 = P1 = P2 = P3 = 0x00;

return;
}

void main(void)
{
init();

while(1)
{
if(timer0_tick == 14) { secs++; timer0_tick = 0; P1 ^= 0x01; }
if(secs == 60) { secs = 0; mins++; P1 ^= 0x02; }
if(mins == 60) { mins = 0; hrs++; P1 ^= 0x04; }
if(hrs == 24) { hrs = 0; P1 ^= 0x08; }
}
}