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77 lines
1.5 KiB
77 lines
1.5 KiB
#include <avr/io.h>
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#include <stdint.h>
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#include <stdbool.h>
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#include "calc.h"
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#include "adc.h"
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/** Initialize the ADC */
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void adc_init(enum ADC_Prescaller presc)
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{
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ADCSRA |= presc; // 128 prescaler -> 125 kHz
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ADMUX |= _BV(REFS0); // Voltage reference
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sbi(ADCSRA, ADEN); // Enable ADC
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}
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/** Disable ADC */
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void adc_disable(void)
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{
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cbi(ADCSRA, ADEN);
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}
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/** Enable ADC */
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void adc_enable(void)
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{
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sbi(ADCSRA, ADEN);
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}
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/** Start a new conversion */
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void adc_start_conversion(uint8_t channel)
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{
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set_low_nibble(ADMUX, channel); // Select channel to sample
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cbi(ADMUX, ADLAR); // Align result to right
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sbi(ADCSRA, ADSC); // Start conversion
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}
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/** Check if ADC is done converting */
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bool adc_ready(void)
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{
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return bit_is_low(ADCSRA, ADSC);
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}
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/** Read the result of last conversion with 8bit precision */
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uint8_t adc_read_8bit()
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{
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uint8_t low = ADCL;
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uint8_t high = ADCH;
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return low >> 2 | high << 6;
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}
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/** Read the result of last conversion with 10bit precision */
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uint16_t adc_read_10bit()
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{
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uint8_t low = ADCL;
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uint8_t high = ADCH;
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return ((uint16_t) high << 8) | low;
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}
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/** Start ADC conversion and wait for the result */
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static void adc_convert(uint8_t channel)
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{
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adc_start_conversion(channel);
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while (!adc_ready()); // Wait for it...
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}
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/** Sample analog pin with 8-bit precision */
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uint8_t adc_convert_8bit(uint8_t channel)
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{
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adc_convert(channel);
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return adc_read_8bit();
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}
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/** Sample analog pin with 10-bit precision */
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uint16_t adc_convert_10bit(uint8_t channel)
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{
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adc_convert(channel);
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return adc_read_10bit();
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}
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