Hi all,

One of my biggest problems has always been using the internal timers of the
PICs.  I'm using a pic16f870 for this little project, and am running into a
problem, I think it's the way I have setup my timers/interrupts, but I am
not sure - I'm hoping someone can enlighten me before I get much farther
into the code.

Basically, the code is designed to count up on port A ~ every ms.

The timer overflow happens ~ .1ms, I have a counter that increments every
time the interrupt is triggered.  This is being done with Timer0

My second timer is causing an interrupt every ~4us, allowing me to turn on
and off bits on port C for any length of time from 0 time on to 250
increments of time on.

But, it doesn't seem to want to toggle, I'm thinking port A toggling is the
problem - by the time I can see everything on my scope, port C is fixed low,
which *might* imply that the counter I have in the second interrupt has
exceeded my set counts and is now perma-low.  But I am not sure.

I have programmed this in CCCS' C, here is the source...


// setup by CCCs
#include <16F870.h>
#device adc=8
#use delay(clock=20000000)
#fuses HS,NOWDT,NOLVP

// structure for dutycycles
typedef struct _DC {
         int8 Duty1, Duty2, Duty3;
         int8 dc1,dc2,dc3;
         int1 curphase1, curphase2, curphase3;
         }stDutyCycle;

int8 curselect,
     curedit;   //unused

int8 count;
int8 curstate, prevstate ;// unused
stDutyCycle DC[3];

#int_RB
RB_isr() {
/*   RB_ISR was created by compiler, but I wanted timer0 used instead,
     this could be part of my problem, not sure.

   int8 B;
   B = input_b();
   if (b
   if (b&0x01)
   {
     if (toggled)
       toggle = 0;
   }
   else
   {
    curedit++;
    if (curedit == 3)
     curedit = 0;
    toggled = 1;
   }*/


}

#int_TIMER2
TIMER2_isr() {

   DC[curselect].dc1++;
   DC[curselect].dc2++;
   DC[curselect].dc3++;

   if (DC[curselect].dc1>DC[curselect].Duty1)
     output_low(PIN_C0);
   if (DC[curselect].dc2>DC[curselect].Duty2)
     output_low(PIN_C1);
   if (DC[curselect].dc3>DC[curselect].Duty3)
     output_low(PIN_C3);



}

#int_TIMER0
TIMER0_isr() {

  count++;
  if (count==9)
   {
    count = 0;
    DC[curselect].dc1 = DC[curselect].dc2 = DC[curselect].dc1 = 0;
    output_c(0x00);
    if (curselect == 2)
     curselect = 0 ;
    else
     curselect++;
    output_a(curselect);
    if (DC[curselect].Duty1>0)
     output_high(PIN_C0);
    if (DC[curselect].Duty2>0)
     output_high(PIN_C1);
    if (DC[curselect].Duty3>0)
     output_high(PIN_C2);


   }
}


void main() {
   count = curselect = 0;

   DC[0].dc1 = DC[0].dc2 = DC[0].dc3 = DC[1].dc1 = DC[1].dc2 = DC[1].dc3 =
     DC[2].dc1 = DC[2].dc2 = DC[2].dc3 = 0;

   DC[0].Duty1 = 150;
   DC[0].Duty2 = 180;
   DC[0].Duty3 = 100;

   DC[1].Duty1 = 0;
   DC[1].Duty2 = 180;
   DC[1].Duty3 = 130;

   DC[2].Duty1 = 100;
   DC[2].Duty2 = 130;
   DC[2].Duty3 = 0;

   set_tris_a(0x00);
   set_tris_c(0x00);

   setup_adc_ports(NO_ANALOGS);
   setup_adc(ADC_OFF);
   setup_psp(PSP_DISABLED);
   setup_spi(FALSE);
   //setup_counters(RTCC_INTERNAL,RTCC_DIV_2);
   setup_timer_0(RTCC_INTERNAL|RTCC_DIV_2);
   setup_timer_1(T1_DISABLED);
   setup_timer_2(T2_DIV_BY_1,20,1);
   //enable_interrupts(INT_RB);
   enable_interrupts(INT_TIMER2);
   enable_interrupts(INT_TIMER0);
   enable_interrupts(global);
   output_a(0);
   output_c(0);

   while (1);

}



Any suggestions would be most appreciated.

-Tony

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