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

[Rune Christensen]

Hello

I think that the clock is okay but Andrew needs to check it.
I should be okay because when Andrew puts TCNT0 directly out to PORTB it
counts like it should be.

Please look at page 42 in
http://www.atmel.com/dyn/resources/prod_documents/Doc0945.pdf
about special care needed when running timer0 with a seperate crystal.

I use this code on a 8515 without any kind of problems:
(Remember this is running on the main clock not a seperate one)

/* time.h */

#define TIMERINI 256-72
#define TIMERCON 0x05

void inittime(void);

/* time.c */

#include<avr/io.h>
#include<avr/interrupt.h>
#include<avr/signal.h>
#include"../main.h"
#include"time.h"

volatile quad uptime;

SIGNAL(SIG_OVERFLOW0)
{
  /* reinitialize timer */
  TCNT0 = TIMERINI;

  uptime++;
}

void inittime(void)
{
  TCCR0 = TIMERCON;
  TCNT0 = TIMERINI;
  TIMSK |= 1<<TOIE0;

  uptime = 0;
}

To Peter:
(Is outcomment proper english?)
I have just looked at the OXFORD Advanced Learner's Dictionary and when out
is used in the beginning of a word it means to expand or similar things e.g.
outbuilding. So outcomment must be to expand the comment :-)

-----Original Message-----
From: address@hidden
[mailto:address@hidden Behalf Of Peter Hierholzer
Sent: Thursday, May 27, 2004 9:02 AM
To: 'Andrew McNabb'; address@hidden
Subject: AW: [avr-gcc-list] Timer Interrupt Problem on ATmega 103L


Hi Andrew,

I have checked your code in the AVRStudio Simulator and it is working fine.

With the statement ASSR = _BV(AS0); your are using a separate crystal as
clock source for timer0. It looks like that this clock does not work.

Did you connect a 32 kHz crystal to TOSC1 and TOSC2?
Is it oscillating?
Does it work if you outcomment the line ASSR = _BV(AS0);
(Is outcomment proper english?)

mfg

Peter



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