81 lines
2.7 KiB
C
81 lines
2.7 KiB
C
#include <avr/io.h>
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#include <util/delay.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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// Table 16-4 : Waveform Generation Mode Bit Description
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#define CTC_TOP_OCR1A_IN_TCCR1B (0<<WGM13 | 1<<WGM12)
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#define CTC_TOP_OCR1A_IN_TCCR1A (0<<WGM11 | 0<<WGM10)
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#define CTC_TOP_ICR1_IN_TCCR1B (1<<WGM13 | 1<<WGM12)
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#define CTC_TOP_ICR1_IN_TCCR1A (0<<WGM11 | 0<<WGM10)
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#define FAST_PWM_TOP_OCR1A_IN_TCCR1B (1<<WGM13 | 1<<WGM12)
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#define FAST_PWM_TOP_OCR1A_IN_TCCR1A (1<<WGM11 | 1<<WGM10)
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#define FAST_PWM_TOP_ICR1_IN_TCCR1B (1<<WGM13 | 1<<WGM12)
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#define FAST_PWM_TOP_ICR1_IN_TCCR1A (1<<WGM11 | 0<<WGM10)
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// END MACROS
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typedef struct {
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int duty_cycle;
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int max;
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int min;
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} IncrementParams;
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void increment_duty_cycle(void *param) {
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IncrementParams *params = (IncrementParams *)param;
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if(params->duty_cycle < params->max) {
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params->duty_cycle += 10;
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}
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OCR1A = TIME_MS(PERCENT(params->duty_cycle, PERIOD), PRESCALE_VALUE);
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}
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void decrement_duty_cycle(void *param) {
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IncrementParams *params = (IncrementParams *)param;
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if(params->duty_cycle > params->min) {
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params->duty_cycle -= 10;
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}
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OCR1A = TIME_MS(PERCENT(params->duty_cycle, PERIOD), PRESCALE_VALUE);
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}
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void on_press(int bit, void (*action)(void*), void *params) {
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if ((TEST(PIND, bit)) == 0) {
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action(params);
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_delay_ms(20);
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while ((TEST(PIND, bit)) == 0) {
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continue;
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}
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_delay_ms(20);
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}
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}
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// led turns on and off every PERIOD ms using Fast PWM timer, with duty cycle controlled by SW1 and SW2
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int main() {
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int duty_cycle = DUTY_CYCLE;
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int max = 100;
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int min = 0;
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IncrementParams params = {duty_cycle, max, min};
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MODE_OUTPUT(LED2);
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TCCR1A |= FAST_PWM_TOP_ICR1_IN_TCCR1A; // Table 16-4 : set timer in Fast PWM (Pulse With Modulation) mode with TOP = ICR1 (Mode 14)
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TCCR1B |= FAST_PWM_TOP_ICR1_IN_TCCR1B;
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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 in 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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on_press(SW1, increment_duty_cycle, ¶ms);
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on_press(SW2, decrement_duty_cycle, ¶ms);
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}
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} |