[avr-gcc-list] AVR simulator and interrupts

[James Fitzsimons]

Hi all,
I am new to the AVR and am trying to write a few simple test programs
before I get my stk500 and real parts. I have downloaded and installed
Klaus's avr simulator, and have managed to get it working with DDD and
avr-gdb.

I can single step through my program and watch variable values as they
change, however for some reason my Timer0 interrupt routine doesn't get
called.

I am using the build of the simulator found here
(http://home.comcast.net/~Bill5107/index.html) and am running it with
the command "simulavr -d at90s8515 -g".

I have included my (extremely simple) program below. It is more than
likely my own programming that is in error, so if anyone can help I
would very much appreciate it.

Cheers,
James Fitzsimons

#include <avr/io.h>             // include I/O definitions (port names, pin
names, etc)
#include <avr/signal.h>         // include "signal" names (interrupt
names)
#include <avr/interrupt.h>      // include interrupt support
#include <avr/eeprom.h>
//#include "global.h"           // include our global settings
#include <avr/timer.h>          // include timer function library
(timing, PWM, etc)

volatile char flag;
volatile unsigned int clk;

void main(void)
{
   int i=0;
 
   flag = 0;
  
  clk = TCNT0 = 0;
  
  TIFR = 1<<TOV0;
  TIMSK = 1<<TOIE0;
  
  // timer stuff
  timer0_source( CK );  //      Writes 'src' into the TCCR0 register.
  timer0_start();
  
  for(i=0; i < 1000; i++)
          clk = TCNT0;
  
  timer0_stop(); //     Stops Timer 0 by clearing the TCNT0 register.

}
 
 
SIGNAL(SIG_OVERFLOW0)
{
        flag = ~flag;
}