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#include <avr/interrupt.h>
#include <avr/io.h>
volatile unsigned short adc_value = 0x5555;
volatile unsigned char complete = 0;
volatile unsigned char in_loop = 0;
void init(void) {
#ifdef ADC_GAIN200
// ADMUX: channel 10, ADLAR = 0, REFS = 3
ADMUX = 0xca;
#else
// ADMUX: channel 18, ADLAR = 0, REFS = 3
ADMUX = 0xd2;
#endif
// ADEN = 1, ADIE = 0, ADPS = 5 CKx32 = 125kHz
ADCSRA = 0x85;
}
int main(void) {
init();
// start ADC
ADCSRA = 0xc5;
do {
in_loop = 1;
if((complete == 0) && ((ADCSRA & _BV(ADSC)) == 0)) {
// read ADC value
adc_value = ADCL | (ADCH << 8);
complete = 1;
}
if(complete == 2) {
#ifdef ADC_GAIN200
// change channel to channel 11
ADMUX = 0xcb;
#else
// change channel to channel 19
ADMUX = 0xd3;
#endif
// start next conversion
complete = 0;
ADCSRA |= _BV(ADSC);
}
} while(1); // do forever
}
// EOF
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