28 lines
858 B
C
28 lines
858 B
C
#include <stdint.h>
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#include <avr/io.h>
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#include <avr/interrupt.h>
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void adcInit(void) {
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// Set reference voltage to AVcc (REFS0 = 1, REFS1 = 0)
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ADMUX = (1 << REFS0);
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// Enable ADC and set prescaler to 128 (for 16 MHz clock, gives 125 kHz ADC clock)
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ADCSRA = (1 << ADEN) | (1 << ADPS2) | (1 << ADPS1) | (1 << ADPS0);
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}
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uint16_t adcRead(uint8_t channel) {
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// Select ADC pin (A0-A7) by setting MUX bits in ADMUX
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// Pins A6 and A7 would make an 8 sensor array possible (for large vases).
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// Achievable only when using the 328p as a DIP, through port C (PC6, PC7)
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ADMUX = (ADMUX & 0xF8) | (channel & 0x07);
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// Start conversion
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ADCSRA |= (1 << ADSC);
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// Wait for conversion to complete (ADSC becomes '0' when done)
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while (ADCSRA & (1 << ADSC));
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// Read ADC (reading order: ADCL --> ADCH)
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return ADC;
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}
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