72 lines
1.0 KiB
C
72 lines
1.0 KiB
C
#include <pentabug/photons.h>
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#include <avr/io.h>
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#include <pentabug/hal.h>
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#include <pentabug/lifecycle.h>
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void photons_init(void) {
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ADCSRA |= (1 << ADEN);
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}
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void photons_stop(void) {
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ADCSRA &= ~(1 << ADEN);
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}
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uint8_t photons_measure(void) {
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// save old state
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uint8_t old_right = led_state(RIGHT);
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uint8_t old_left = led_state(LEFT);
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// all leds off
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led_off(RIGHT);
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led_off(LEFT);
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// set to ground for discharge
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DDRC |= 1 << 3;
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PORTC &= ~(1 << 3);
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// wait for discharge
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wait_ms(1);
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// set direction to input for measurement
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DDRC &= ~(1 << 3);
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// collect some photons
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wait_ms(1);
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// start measurement
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// TODO: why can't i move this to the initialization?
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ADMUX = (1 << REFS0) | (1 << ADLAR);
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ADCSRA |= (1 << ADPS2) | (1 << ADPS1);
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ADMUX = (ADMUX & ~(0x1F)) | 3;
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ADCSRA |= (1 << ADSC);
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// wait for measurement to finish
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while (ADCSRA & (1 << ADSC)) test_stop_app();
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uint8_t res = ADCH;
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// restore state
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PORTC |= 1 << 3;
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DDRC |= 1 << 3;
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led_set(RIGHT, old_right);
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led_set(LEFT, old_left);
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// done
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return res;
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}
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