28 lines
1.1 KiB
C
28 lines
1.1 KiB
C
#include <avr/io.h>
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#include "utils.h"
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#include "bitmanip.h"
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#include "timer.h"
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#define PERIOD 1000
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#define PRESCALE_VALUE 1024 // can be 1, 8, 64, 256, 1024
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#define DUTY_CYCLE 10
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// turns on led2 at 1Hz and duty cycle of 10%, not using PORTx, with empty infinite loop
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int main() {
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MODE_OUTPUT(LED2);
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SET(TCCR1A, WGM11); // Table 16-4 : set timer in Fast PWM (Pulse With Modulation) mode with TOP = ICR1 (Mode 14)
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SET(TCCR1B, WGM12);
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SET(TCCR1B, WGM13);
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SET(TCCR1A, COM1A1); // Table 16-2 : non-inverting mode, the LED will be ON for DUTY_CYCLE% of the time (CLEAR OC1A on compare match, SET OC1A at BOTTOM)
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ICR1 = TIME_MS(PERIOD, PRESCALE_VALUE); // Table 16-4 : set the period (compare TOP value)
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OCR1A = TIME_MS(PERCENT(DUTY_CYCLE, PERIOD), PRESCALE_VALUE); // 16.9.3 : set the duty cycle to DUTY_CYCLE% of the time on channel A -> OC1A (alternate function of PORTB1, aka LED2) is cleared when TCNT1 (the counter value) equals OCR1A
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TCCR1B |= (PRESCALE_SET(PRESCALE_VALUE)); // start the timer with the prescaler
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while(1);
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} |