From c99ed77e3748c27ea2c4d075be90c744bdeff9bd Mon Sep 17 00:00:00 2001 From: "Matthias P. Braendli" Date: Sun, 29 Dec 2019 22:34:59 +0100 Subject: Read ADCL before ADCH --- sw/main.cpp | 8 ++++++-- 1 file changed, 6 insertions(+), 2 deletions(-) diff --git a/sw/main.cpp b/sw/main.cpp index c9ecd04..894693a 100644 --- a/sw/main.cpp +++ b/sw/main.cpp @@ -475,7 +475,10 @@ int main() // ADSC is cleared when the conversion finishes if ((ADCSRA & ADSC) == 0) { // BAT+ - const uint16_t adc_value_0 = ((uint16_t)ADCH << 8) | ADCL; + + // Datasheet 24.9.3 says ADCL must be read first + const uint8_t adcl = ADCL; + const uint16_t adc_value_0 = ((uint16_t)ADCH << 8) | adcl; send_voltage(ADC_VALUE_TO_MILLIVOLT(adc_value_0) * 4, true, time_now); SET_ADMUX(1); // Start ADC conversion @@ -488,7 +491,8 @@ int main() // ADSC is cleared when the conversion finishes if ((ADCSRA & ADSC) == 0) { // BAT- - const uint16_t adc_value_1 = ((uint16_t)ADCH << 8) | ADCL; + const uint8_t adcl = ADCL; + const uint16_t adc_value_1 = ((uint16_t)ADCH << 8) | adcl; adc_state = adc_state_t::IDLE; send_voltage(ADC_VALUE_TO_MILLIVOLT(adc_value_1) * 4, false, time_now); -- cgit v1.2.3