2 files changed, 29 insertions, 28 deletions

diff --git a/src/components/battery/BatteryController.cpp b/src/components/battery/BatteryController.cpp
index b39efefb..fa476ea3 100644
--- a/src/components/battery/BatteryController.cpp
+++ b/src/components/battery/BatteryController.cpp
@@ -1,9 +1,7 @@
 #include "BatteryController.h"
 #include <hal/nrf_gpio.h>
 #include <nrfx_saadc.h>
-#include <libraries/log/nrf_log.h>
 #include <algorithm>
-#include <math.h>
 
 using namespace Pinetime::Controllers;
 
@@ -14,17 +12,16 @@ Battery::Battery() {
 }
 
 void Battery::Init() {
-  nrf_gpio_cfg_input(chargingPin, (nrf_gpio_pin_pull_t) GPIO_PIN_CNF_PULL_Pullup);
-  nrf_gpio_cfg_input(powerPresentPin, (nrf_gpio_pin_pull_t) GPIO_PIN_CNF_PULL_Pullup);
+  nrf_gpio_cfg_input(chargingPin, static_cast<nrf_gpio_pin_pull_t> GPIO_PIN_CNF_PULL_Pullup);
 }
 
 void Battery::Update() {
-
   isCharging = !nrf_gpio_pin_read(chargingPin);
   isPowerPresent = !nrf_gpio_pin_read(powerPresentPin);
 
-  if (isReading)
+  if (isReading) {
     return;
+  }
   // Non blocking read
   samples = 0;
   isReading = true;
@@ -33,13 +30,13 @@ void Battery::Update() {
   nrfx_saadc_sample();
 }
 
-void Battery::adcCallbackStatic(nrfx_saadc_evt_t const* event) {
+void Battery::AdcCallbackStatic(nrfx_saadc_evt_t const* event) {
   instance->SaadcEventHandler(event);
 }
 
 void Battery::SaadcInit() {
   nrfx_saadc_config_t adcConfig = NRFX_SAADC_DEFAULT_CONFIG;
-  APP_ERROR_CHECK(nrfx_saadc_init(&adcConfig, adcCallbackStatic));
+  APP_ERROR_CHECK(nrfx_saadc_init(&adcConfig, AdcCallbackStatic));
 
   nrf_saadc_channel_config_t adcChannelConfig = {.resistor_p = NRF_SAADC_RESISTOR_DISABLED,
                                                  .resistor_n = NRF_SAADC_RESISTOR_DISABLED,
@@ -55,23 +52,23 @@ void Battery::SaadcInit() {
 }
 
 void Battery::SaadcEventHandler(nrfx_saadc_evt_t const* p_event) {
-
-  const float battery_max = 4.18; // maximum voltage of battery ( max charging voltage is 4.21 )
-  const float battery_min = 3.20; // minimum voltage of battery before shutdown ( depends on the battery )
+  const uint16_t battery_max = 4180; // maximum voltage of battery ( max charging voltage is 4.21 )
+  const uint16_t battery_min = 3200; // minimum voltage of battery before shutdown ( depends on the battery )
 
   if (p_event->type == NRFX_SAADC_EVT_DONE) {
 
     APP_ERROR_CHECK(nrfx_saadc_buffer_convert(&saadc_value, 1));
 
-    voltage = (static_cast<float>(p_event->data.done.p_buffer[0]) * 2.04f) / (1024 / 3.0f);
-    voltage = roundf(voltage * 100) / 100;
-
-    percentRemaining = static_cast<int>(((voltage - battery_min) / (battery_max - battery_min)) * 100);
-
+    // 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
+    // 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;
+    percentRemaining = (voltage - battery_min) * 100 / (battery_max - battery_min);
     percentRemaining = std::max(percentRemaining, 0);
     percentRemaining = std::min(percentRemaining, 100);
-
-    percentRemainingBuffer.insert(percentRemaining);
+    percentRemainingBuffer.Insert(percentRemaining);
 
     samples++;
     if (samples > percentRemainingSamples) {
diff --git a/src/components/battery/BatteryController.h b/src/components/battery/BatteryController.h
index 04bcf6b8..1333ad0e 100644
--- a/src/components/battery/BatteryController.h
+++ b/src/components/battery/BatteryController.h
@@ -19,7 +19,7 @@ namespace Pinetime {
      insert member function overwrites the next data to the current
     HEAD and moves the HEAD to the newly inserted value.
     */
-      void insert(const int num) {
+      void Insert(const uint8_t num) {
         head %= cap;
         arr[head++] = num;
         if (sz != cap) {
@@ -27,13 +27,13 @@ namespace Pinetime {
         }
       }
 
-      int GetAverage() const {
+      uint8_t GetAverage() const {
         int sum = std::accumulate(arr.begin(), arr.end(), 0);
-        return (sum / sz);
+        return static_cast<uint8_t>(sum / sz);
       }
 
     private:
-      std::array<int, N> arr; /**< internal array used to store the values*/
+      std::array<uint8_t, N> arr; /**< internal array used to store the values*/
       uint8_t sz;             /**< The current size of the array.*/
       uint8_t cap;            /**< Total capacity of the CircBuffer.*/
       uint8_t head;           /**< The current head of the CircBuffer*/
@@ -46,17 +46,21 @@ namespace Pinetime {
       void Init();
       void Update();
 
-      int PercentRemaining() const {
-        return percentRemainingBuffer.GetAverage();
+      uint8_t PercentRemaining() const {
+        auto avg = percentRemainingBuffer.GetAverage();
+        avg = std::min(avg, static_cast<uint8_t>(100));
+        avg = std::max(avg, static_cast<uint8_t>(0));
+        return avg;
       }
 
-      float Voltage() const {
+      uint16_t Voltage() const {
         return voltage;
       }
 
       bool IsCharging() const {
         return isCharging;
       }
+
       bool IsPowerPresent() const {
         return isPowerPresent;
       }
@@ -71,7 +75,7 @@ namespace Pinetime {
       static constexpr uint32_t chargingPin = 12;
       static constexpr uint32_t powerPresentPin = 19;
       static constexpr nrf_saadc_input_t batteryVoltageAdcInput = NRF_SAADC_INPUT_AIN7;
-      float voltage = 0.0f;
+      uint16_t voltage = 0;
       int percentRemaining = -1;
 
       bool isCharging = false;
@@ -80,10 +84,10 @@ namespace Pinetime {
       void SaadcInit();
 
       void SaadcEventHandler(nrfx_saadc_evt_t const* p_event);
-      static void adcCallbackStatic(nrfx_saadc_evt_t const* event);
+      static void AdcCallbackStatic(nrfx_saadc_evt_t const* event);
 
       bool isReading = false;
       uint8_t samples = 0;
     };
   }
-}
\ No newline at end of file
+}