59 lines
1.3 KiB
C
59 lines
1.3 KiB
C
#include <stdint.h>
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#include <avr/interrupt.h>
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#include <avr/common.h>
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#include <avr/io.h>
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#include "util.h"
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static volatile uint8_t internal_counter;
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void timer_init(void) {
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/* initialize timer2, CTC at 10ms, prescaler 1024 */
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OCR2A = F_CPU / 1024 / 100;
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TCCR2A = _BV(WGM21);
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TCCR2B = _BV(CS22) | _BV(CS21) | _BV(CS20);
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TIMSK2 = _BV(OCIE2A);
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}
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void timer_set(timer_t *t, uint8_t timeout) {
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t->current = internal_counter;
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t->timeout = timeout;
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}
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void timerL_set(timerL_t *t, uint16_t timeout) {
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t->current = internal_counter;
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t->timeout = timeout;
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}
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bool timer_expired(timer_t *t) {
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if (t->timeout == 0)
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return true;
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/* attention: may fail if internal counter is incremented by more than one
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* between two calls of timer_expired()! (that is if its is called less than every 10ms*/
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if (t->current != internal_counter) {
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t->timeout--;
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t->current = internal_counter;
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}
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return false;
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}
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bool timerL_expired(timerL_t *t) {
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if (t->timeout == 0)
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return true;
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/* attention: may fail if internal counter is incremented by more than one
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* between two calls of timer_expired()! */
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if (t->current != internal_counter) {
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t->timeout--;
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t->current = internal_counter;
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}
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return false;
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}
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/* timer interrupt function */ISR(TIMER2_COMPA_vect, ISR_NOBLOCK) {
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internal_counter++;
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}
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