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/*
* (C) Copyright 2014 Leo C. <erbl259-lmu@yahoo.de>
*
* SPDX-License-Identifier: GPL-2.0
*/
#include "timer.h"
#include <avr/interrupt.h>
#include <util/atomic.h>
#include "time.h"
/* timer interrupt/overflow counter */
/* counts up every ms. */
static volatile
uint32_t timestamp;
/*
* 1000Hz timer interrupt generated by OC4A
*/
ISR(TIMER4_COMPA_vect)
{
static int_fast8_t tick_10ms;
static int_fast8_t tick_1s;
int_fast8_t i, j;
extern void disk_timerproc(void);
OCR4A += F_CPU / 1000; /* 1000Hz interval */
timestamp++;
i = tick_10ms + 1;
if (i == 10) {
Stat |= S_10MS_TO;
/* Drive timer procedure of low level disk I/O module */
disk_timerproc();
j = tick_1s - 1;
if (j == 0) {
system_tick();
j = 100;
}
tick_1s = j;
i = 0;
}
tick_10ms = i;
}
/*--------------------------------------------------------------------------*/
void setup_timer(void)
{
PRR1 &= ~_BV(PRTIM4);
OCR4A = F_CPU / 1000 - 1; /* Timer4: 1000Hz interval */
TCCR4B = (0b00<<WGM42)|(0b001<<CS40); /* Normal Mode, Prescaler 1 */
TIMSK4 = _BV(OCIE4A); /* Enable Output Compare A interrupt */
}
/*--------------------------------------------------------------------------*/
uint32_t get_timer(uint32_t base)
{
uint32_t ret;
ATOMIC_BLOCK(ATOMIC_FORCEON)
{
ret = timestamp;
}
return ret - base;
}
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