Increase ADC precision

Author: Riksu9000

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;