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[z180-stamp.git] / avr / timer.c

/*
 * (C) Copyright 2014 Leo C. <erbl259-lmu@yahoo.de>
 *
 * SPDX-License-Identifier:	GPL-2.0+
 */

#include "common.h"
#include <avr/interrupt.h>
#include <util/atomic.h>
#include "time.h"
#include "timer.h"

/* timer interrupt/overflow counter */
/* counts up every ms. */
static volatile
uint32_t timestamp;

/*
 * 1000Hz timer interrupt generated by OC3A
 */
ISR(TIMER3_COMPA_vect)
{
	static int_fast8_t tick_10ms;
	static int_fast8_t tick_1s;
	int_fast8_t i, j;

	extern void disk_timerproc(void);

	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;
}


/*--------------------------------------------------------------------------*/

#if 0
void timer_setup(void)
{

	/* Clock */
	CLKPR = _BV(CLKPCE);
	CLKPR = 0;

	/* Timer */

	OCR1A = F_CPU / 1000 - 1; // Timer1: 1000Hz interval (OC1A)
	TCCR1B = 0b00001001;
	TIMSK1 = _BV(OCIE1A); // Enable TC1.oca interrupt
}
#endif

/*--------------------------------------------------------------------------*/

uint32_t get_timer(uint32_t base)
{
	uint32_t ret;
	ATOMIC_BLOCK(ATOMIC_FORCEON)
	{
		ret = timestamp;
	}
	return ret - base;
}