2 files changed, 67 insertions, 54 deletions

diff --git a/src/components/battery/BatteryController.cpp b/src/components/battery/BatteryController.cpp
index aaa245e4..50f95c99 100644
--- a/src/components/battery/BatteryController.cpp
+++ b/src/components/battery/BatteryController.cpp
@@ -1,16 +1,38 @@
 #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;
 
+#define SAMPLES_IN_BUFFER 1
+static nrf_saadc_value_t m_buffer_pool[2][SAMPLES_IN_BUFFER];
+
+static float voltage = 0.0f;
+static int percentRemaining = -1;
+
 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);
+}
+
+void Battery::Update() {
 
+  isCharging = !nrf_gpio_pin_read(chargingPin);
+  isPowerPresent = !nrf_gpio_pin_read(powerPresentPin);
+  
+  // Non blocking read
+  SaadcInit();
+  nrfx_saadc_sample();
+  
+}
+
+void Battery::SaadcInit() {
   nrfx_saadc_config_t adcConfig = NRFX_SAADC_DEFAULT_CONFIG;
-  nrfx_saadc_init(&adcConfig, SaadcEventHandler);
+  APP_ERROR_CHECK(nrfx_saadc_init(&adcConfig, SaadcEventHandler));
+
   nrf_saadc_channel_config_t adcChannelConfig = {
           .resistor_p = NRF_SAADC_RESISTOR_DISABLED,
           .resistor_n = NRF_SAADC_RESISTOR_DISABLED,
@@ -18,32 +40,50 @@ void Battery::Init() {
           .reference  = NRF_SAADC_REFERENCE_INTERNAL,
           .acq_time   = NRF_SAADC_ACQTIME_3US,
           .mode       = NRF_SAADC_MODE_SINGLE_ENDED,
-          .burst      = NRF_SAADC_BURST_DISABLED,
+          .burst      = NRF_SAADC_BURST_ENABLED,
           .pin_p      = batteryVoltageAdcInput,
           .pin_n      = NRF_SAADC_INPUT_DISABLED
   };
-  nrfx_saadc_channel_init(0, &adcChannelConfig);
+  APP_ERROR_CHECK(nrfx_saadc_channel_init(0, &adcChannelConfig));
+  APP_ERROR_CHECK(nrfx_saadc_buffer_convert(m_buffer_pool[0],SAMPLES_IN_BUFFER));
+  APP_ERROR_CHECK(nrfx_saadc_buffer_convert(m_buffer_pool[1],SAMPLES_IN_BUFFER));
+
 }
 
-void Battery::Update() {
-  isCharging = !nrf_gpio_pin_read(chargingPin);
-  isPowerPresent = !nrf_gpio_pin_read(powerPresentPin);
+void Battery::SaadcEventHandler(nrfx_saadc_evt_t const * p_event) {
+  int avg_sample = 0;
+  int i = 0;
+
+  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 )
 
-  nrf_saadc_value_t value = 0;
-  nrfx_saadc_sample_convert(0, &value);
+  if (p_event->type == NRFX_SAADC_EVT_DONE) {
+    
+    APP_ERROR_CHECK(nrfx_saadc_buffer_convert(p_event->data.done.p_buffer, SAMPLES_IN_BUFFER));
 
-  // see https://forum.pine64.org/showthread.php?tid=8147
-  voltage = (value * 2.0f) / (1024/3.0f);
-  int percentRemaining = ((voltage - 3.55f)*100.0f)*3.9f;
-  percentRemaining = std::max(percentRemaining, 0);
-  percentRemaining = std::min(percentRemaining, 100);
+    for (i = 0; i < SAMPLES_IN_BUFFER; i++) {
+      avg_sample += p_event->data.done.p_buffer[i]; // take N samples in a row
+    }
+    avg_sample /= i; // average all the samples out
 
-  percentRemainingBuffer.insert(percentRemaining);
+    voltage = (static_cast<float>(avg_sample) * 2.04f) / (1024 / 3.0f);
+    voltage = roundf(voltage * 100) / 100;
 
-//  NRF_LOG_INFO("BATTERY " NRF_LOG_FLOAT_MARKER " %% - " NRF_LOG_FLOAT_MARKER " v", NRF_LOG_FLOAT(percentRemaining), NRF_LOG_FLOAT(voltage));
-//  NRF_LOG_INFO("POWER Charging : %d - Power : %d", isCharging, isPowerPresent);
+    percentRemaining = static_cast<int>(((voltage - battery_min) / (battery_max - battery_min)) * 100);
+
+    percentRemaining = std::max(percentRemaining, 0);
+    percentRemaining = std::min(percentRemaining, 100);
+
+    nrfx_saadc_uninit();
+
+  }
 }
 
-void Battery::SaadcEventHandler(nrfx_saadc_evt_t const * event) {
 
+int Battery::PercentRemaining() {
+  return percentRemaining;
+}
+
+float Battery::Voltage() {
+  return voltage;
 }
\ No newline at end of file
diff --git a/src/components/battery/BatteryController.h b/src/components/battery/BatteryController.h
index 86250a57..9bc942c9 100644
--- a/src/components/battery/BatteryController.h
+++ b/src/components/battery/BatteryController.h
@@ -6,44 +6,16 @@
 
 namespace Pinetime {
   namespace Controllers {
-  /** A simple circular buffer that can be used to average 
-   out the sensor values. The total capacity of the CircBuffer  
-   is given as the template parameter N.
-   */ 
-  template <int N> 
-  class CircBuffer {
-  public:
-    CircBuffer() : arr{}, sz{}, cap{N}, head{} {}
-    /**
-   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) {
-      head %= cap;
-      arr[head++] = num;
-      if (sz != cap) {
-        sz++;
-      }
-    }
-
-    int GetAverage() const {
-      int sum = std::accumulate(arr.begin(), arr.end(), 0);
-      return (sum / sz);
-    }
-
-  private:
-    std::array<int, 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*/
-  };
 
     class Battery {
       public:
+
         void Init();
         void Update();
-        int PercentRemaining() const { return percentRemainingBuffer.GetAverage(); }
-        float Voltage() const { return voltage; }
+        
+        int PercentRemaining();
+        float Voltage();
+
         bool IsCharging() const { return isCharging; }
         bool IsPowerPresent() const { return isPowerPresent; }
 
@@ -51,12 +23,13 @@ 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;
-        static constexpr uint8_t percentRemainingSamples = 10;
-        static void SaadcEventHandler(nrfx_saadc_evt_t const * p_event);
-        CircBuffer<percentRemainingSamples> percentRemainingBuffer {};
-        float voltage = 0.0f;
+
         bool isCharging = false;
         bool isPowerPresent = false;
+
+        static void SaadcEventHandler(nrfx_saadc_evt_t const * p_event);
+        void SaadcInit();
+
     };
   }
 }
\ No newline at end of file