Hi,
[EMAIL PROTECTED] schrieb:
> polling volatile variable TIMEOUT from main() is failed.
does it wait forever or
does it continue to soon or
does it continue irregularly?
> volatile unsigned int TICKS; // system ticks
> volatile unsigned char TIMEOUT; // system timeout flag
> =====
> SYS.C
> =====
> #include <at89x52.h>
> #include "sys.h"
>
> void SystemTick( void ) interrupt 1 using 1 {
> TR0 = 0;
> TL0 = (unsigned char) RELOAD_VALUE;
> TH0 = (unsigned char) ((unsigned int) RELOAD_VALUE >> 8);
> TR0 = 1;
>
> /* system ticks */
> if ( TICKS ) {
> TICKS--;
> return;
> }
> TIMEOUT = 1;
> }
>
> void LoadDelay( unsigned int ticks ) {
> if ( ticks ) {
> TIMEOUT = 0;
> TICKS = ticks;
> }
> }
you would need to protect access to TICKS so the IRQ doesn't interfere.
Also TIMEOUT might be set by the IRQ when you won't expect it.
(bit EA_SAVE=EA; EA=0; ....)
Is the IRQ called? Maybe also toggle a LED there. Like P1_7 = (counter++ &
0x80);
Two other notes:
"using 1" or "__using(1)" is not needed (you do not use r0..r7
in the IRQ).
Surprisingly often using "using" gives very little benefit and
just eats data memory.
volatile unsigned char TIMEOUT;
you could/should use a bit variable there "volatile bit TIMEOUT"
Greetings,
Frieder
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