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#include <avr/io.h>
#include <avr/interrupt.h>
volatile uint32_t dummy = 0;
volatile uint32_t conversions = 0;
volatile uint16_t adc_value = 5555;
ISR(ADC_vect)
{
if((ADCSRA & (1 << ADSC)) == 0)
{
++conversions;
adc_value = ADC;
ADCSRA |= /* ADC Control and Status Register A */
(1 << ADSC); /* ADC Start Conversion */
}
}
int main(void)
{
/* I'm not sure if this is necessary. I think, program startup is
* considered to be handling of the reset interrupt.
* So Interrupts will be disabled at program startup.
* just to be on the safe side: */
cli();
ADCSRA = /* ADC Control and Status Register A */
(1 << ADEN) /* ADC Enable */
| (1 << ADSC) /* ADC Start Conversion */
| (1 << ADIE) /* ADC Interrupt Enable */
| (1<< ADPS2) /* ADPS2...ADPS0 ADC Prescaler Select Bits = 1 0 0, on 4MHz,
factor 16 = 4µs adc clock, conversion time x13 = 52µs normally */
;
ADMUX = /* ADC Multiplexer Select Register */
/* REFS1...REFS0 (ReferenceSelection Bits) = 0 --> Externes AREF */
(0 << MUX2) | (0 << MUX1) | (0 << MUX0); /* MUX4...MUX0 = channel*/
sei();
while(1)
{
++dummy;
}
}
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