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/*
* spreadspace avr utils
*
*
* Copyright (C) 2013 Christian Pointner <equinox@spreadspace.org>
* Othmar Gsenger <otti@wirdorange.org>
*
* This file is part of spreadspace avr utils.
*
* spreadspace avr utils 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
* any later version.
*
* spreadspace avr utils 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 spreadspace avr utils. If not, see <http://www.gnu.org/licenses/>.
*/
#include <avr/sfr_defs.h>
#include <avr/interrupt.h>
#include "led.h"
#include "heartbeat.h"
#define HEARTBEAT_DURATION 10 // *10 ms, duration of heartbeat pulse
#define HEARTBEAT_DELAY 200 // *10 ms, 1/heartbeat-frequency
uint8_t heartbeat_cnt = 0;
uint8_t heartbeat_flag;
// while running this gets called every ~10ms
ISR(TIMER0_COMPA_vect)
{
heartbeat_cnt++;
if(heartbeat_cnt == HEARTBEAT_DURATION)
heartbeat_flag = 0;
else if(heartbeat_cnt >= HEARTBEAT_DELAY) {
heartbeat_flag = 1;
heartbeat_cnt = 0;
}
}
void init_heartbeat(void)
{
led_off();
heartbeat_cnt = 0;
heartbeat_flag = 1;
// timer 2: ~10 ms, timebase for heartbeat signal
TCCR0A = 1<<WGM01; // OC0A and OC0B as normal output, WGM = 2 (CTC)
TCCR0B = 1<<CS02 | 1<<CS00; // Prescaler 1:1024
OCR0A = 155; // (1+155)*1024 = 159744 -> ~10 ms @ 16 MHz
//OCR2A = 194; // (1+194)*1024 = 199680 -> ~10 ms @ 20 MHz
TCNT2 = 0; // reseting timer
TIMSK0 = 1<<OCIE0A; // enable Interrupt
}
void handle_heartbeat(void)
{
if(heartbeat_flag)
led_on();
else
led_off();
}
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