Re: [avr-gcc-list] Timer Interrupt Problem on ATmega 103L

[René Liebscher]

Matthew Arcus schrieb:
> ----- Original Message ----- 
> From: "'Andrew McNabb'" <address@hidden>
> To: "Rune Christensen" <address@hidden>
> Cc: <address@hidden>
> Sent: Thursday, May 27, 2004 10:55 PM
> Subject: Re: [avr-gcc-list] Timer Interrupt Problem on ATmega 103L
>
>
>
> > However when I add something to my while loop that polls TCNT0 to check
> > "manually" whether there's been an overflow, the behavior depends on
> > whether or not I've set TOIE0 in TIMSK.
>
>
> A bit of a long shot - are you definitely compiling for ATmega 103L so you
> are getting the right value for TOIE0 (it's bit 0 on the mega103L, but is
> bit 1 on some (earlier?) processors (the 2313 for example).
>
> Matthew.
>
> > If TOIE0 is not set, everything
> > works properly and the lights flip on and off every second.  However if
> > TOIE0 is set, the lights on PORTB all turn on and stay on.  But if the
> > while loop is empty, the lights stay off.

Even if it is the same bit, it could be the wrong vector number for the 
signal handler. This would result in a reset if the timer overflows. 
Then you get the result which is mentioned above. Lights are switched 
on, timer overflows => RESET, lights switched off for very short period 
of time until they are switched on again in the while loop.


Rene