43 lines
730 B
C
43 lines
730 B
C
#include <stdint.h>
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#include <stdbool.h>
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#include <avr/io.h>
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#include <avr/interrupt.h>
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#include "avr.h"
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/* This only works out for a 16MHz or 8MHz clock */
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#define CLOCK_HZ 16000000
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#define TICKS_PER_SECOND (CLOCK_HZ / 256)
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#define TICKS_PER_JIFFY (TICKS_PER_SECOND / 10)
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#define cbi(byt, bit) (byt &= ~_BV(bit))
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#define sbi(byt, bit) (byt |= _BV(bit))
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extern volatile bool tick;
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extern volatile uint32_t jiffies;
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// Interrupt called every jiffy
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ISR(TIM1_COMPA_vect)
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{
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jiffies += 1;
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tick = true;
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}
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void
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init(void)
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{
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int i;
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DDRA = ~(_BV(NESOUT));
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DDRB = 0xff;
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TCCR1A = 0;
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TCCR1B = 0;
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TCNT1 = 0;
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OCR1A = TICKS_PER_JIFFY - 1;
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TCCR1B |= (1 << WGM12);
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TCCR1B |= (1 << CS12);
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TIMSK1 |= (1 << OCIE1A);
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sei();
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}
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