From 79ee65bfd53d31dd282dbbb7952296cc6f1212eb Mon Sep 17 00:00:00 2001 From: Riku Isokoski Date: Tue, 27 Jul 2021 22:41:48 +0300 Subject: [PATCH] Increase ADC precision --- src/components/battery/BatteryController.cpp | 8 ++++---- 1 file changed, 4 insertions(+), 4 deletions(-) diff --git a/src/components/battery/BatteryController.cpp b/src/components/battery/BatteryController.cpp index 54b9ffd9..e334eeac 100644 --- a/src/components/battery/BatteryController.cpp +++ b/src/components/battery/BatteryController.cpp @@ -39,7 +39,7 @@ void Battery::SaadcInit() { nrf_saadc_channel_config_t adcChannelConfig = {.resistor_p = NRF_SAADC_RESISTOR_DISABLED, .resistor_n = NRF_SAADC_RESISTOR_DISABLED, - .gain = NRF_SAADC_GAIN1_5, + .gain = NRF_SAADC_GAIN1_4, .reference = NRF_SAADC_REFERENCE_INTERNAL, .acq_time = NRF_SAADC_ACQTIME_40US, .mode = NRF_SAADC_MODE_SINGLE_ENDED, @@ -59,11 +59,11 @@ void Battery::SaadcEventHandler(nrfx_saadc_evt_t const* p_event) { APP_ERROR_CHECK(nrfx_saadc_buffer_convert(&saadc_value, 1)); // A hardware voltage divider divides the battery voltage by 2 - // ADC gain is 1/5 - // thus adc_voltage = battery_voltage / 2 * gain = battery_voltage / 10 + // ADC gain is 1/4 + // thus adc_voltage = battery_voltage / 2 * gain = battery_voltage / 8 // reference_voltage is 0.6V // p_event->data.done.p_buffer[0] = (adc_voltage / reference_voltage) * 1024 - voltage = p_event->data.done.p_buffer[0] * 6000 / 1024; + voltage = p_event->data.done.p_buffer[0] * (0.6 * 8 * 1000) / 1024; if (voltage > battery_max) { percentRemaining = 100;