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/*
attiny13_watchdog_test.c
Copyright 2008, 2009 Michel Pollet <buserror@gmail.com>
This file is part of simavr.
simavr is free software: you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation, either version 3 of the License, or
(at your option) any later version.
simavr is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with simavr. If not, see <http://www.gnu.org/licenses/>.
*/
#include <avr/io.h>
#include <stdio.h>
#include <avr/interrupt.h>
#include <util/delay.h>
#include <avr/sleep.h>
#include <avr/wdt.h>
/*
* This demonstrate how to use the avr_mcu_section.h file
* The macro adds a section to the ELF file with useful
* information for the simulator
*/
#include "avr_mcu_section.h"
AVR_MCU(F_CPU, "atmega48");
static int uart_putchar(char c, FILE *stream) {
if (c == '\n')
uart_putchar('\r', stream);
loop_until_bit_is_set(UCSR0A, UDRE0);
UDR0 = c;
return 0;
}
static FILE mystdout = FDEV_SETUP_STREAM(uart_putchar, NULL,
_FDEV_SETUP_WRITE);
ISR(WDT_vect)
{
// nothing to do here, we're just here to wake the CPU
}
int main()
{
stdout = &mystdout;
DDRD = (1<<PD1); // configure TxD as output
wdt_enable(WDTO_120MS);
// enable watchdog interupt
// NOTE: since the Change Enable bit is no longer on, it should not
// change the timer value that is already set!
WDTCSR = (1 << WDIE);
sei();
printf("Watchdog is active\n");
uint8_t count = 20;
while (count--) {
_delay_ms(10);
wdt_reset();
}
printf("Waiting for Watchdog to kick\n");
// now , stop calling the watchdog reset, and just sleep until it fires
sleep_cpu();
printf("Watchdog kicked us!\n");
// when arriving here, the watchdog timer interupt was called and woke up
// the core from sleep, so we can just quit properly
cli();
sleep_cpu();
}
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