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-rw-r--r--src/arch/arduino-nano/driver/adc.cc36
1 files changed, 36 insertions, 0 deletions
diff --git a/src/arch/arduino-nano/driver/adc.cc b/src/arch/arduino-nano/driver/adc.cc
index 17cfc27..8f828a4 100644
--- a/src/arch/arduino-nano/driver/adc.cc
+++ b/src/arch/arduino-nano/driver/adc.cc
@@ -8,6 +8,42 @@
#include "arch.h"
#include "driver/adc.h"
+uint16_t AVRADC::getPin_mV(uint8_t pin, uint16_t avcc)
+{
+ if (avcc) {
+ // measure with AVCC reference
+ ADMUX = _BV(REFS0) | pin;
+ } else {
+ // measure with internal 1.1V bandgap refernce
+ ADMUX = _BV(REFS1) | _BV(REFS0) | pin;
+ }
+
+ // Enable ADC with /64 prescaler
+ ADCSRA = _BV(ADEN) | _BV(ADPS2);
+
+ // Wait for bandgap to stabilise (70us according to datasheet table 28-3)
+ arch.delay_ms(1);
+
+ // Start conversion
+ ADCSRA |= _BV(ADSC);
+
+ // wait until conversion is complete
+ while (ADCSRA & _BV(ADSC)) ;
+
+ uint8_t adcr_l = ADCL;
+ uint8_t adcr_h = ADCH;
+ uint16_t adcr = adcr_l + (adcr_h << 8);
+
+ // Disable ADC
+ ADCSRA &= ~_BV(ADEN);
+
+ if (avcc) {
+ return (uint32_t)avcc * adcr / 1023L;
+ } else {
+ return 1100L * adcr / 1023L;
+ }
+}
+
int16_t AVRADC::getTemp_mdegC(int16_t offset)
{
// Measure temperature probe with 1.1V bandgap reference