From 81f1bc5c7048e8c821267868632e52f886c132e7 Mon Sep 17 00:00:00 2001
From: Verkehrsrot <cyberman@obh.snafu.de>
Date: Sun, 8 Sep 2019 12:55:27 +0200
Subject: [PATCH] Heltecv2 battery monitor

---
 src/hal/heltecv2.h |  5 +++--
 src/power.cpp      | 28 +++++++++++++++++++++-------
 2 files changed, 24 insertions(+), 9 deletions(-)

diff --git a/src/hal/heltecv2.h b/src/hal/heltecv2.h
index 3f6bf743..cc7de4d1 100644
--- a/src/hal/heltecv2.h
+++ b/src/hal/heltecv2.h
@@ -20,8 +20,9 @@
 #define HAS_LED LED_BUILTIN                           // white LED on board
 #define HAS_BUTTON KEY_BUILTIN                        // button "PROG" on board
 
-//#define BAT_MEASURE_ADC ADC2_GPIO13_CHANNEL  // battery probe GPIO pin
-//#define BAT_VOLTAGE_DIVIDER 4 // voltage divider 220k/100k on board
+#define BAT_MEASURE_ADC ADC2_GPIO13_CHANNEL  // battery probe GPIO pin
+#define BAT_MEASURE_ADC_UNIT 2 // ADC 2
+#define BAT_VOLTAGE_DIVIDER 2 // voltage divider 220k/100k on board
 #define EXT_POWER_SW Vext // switches battery power, Vext control 0 = on / 1 = off
 #define EXT_POWER_ON    0
 //#define EXT_POWER_OFF   1
diff --git a/src/power.cpp b/src/power.cpp
index 5797da26..ad366d8b 100644
--- a/src/power.cpp
+++ b/src/power.cpp
@@ -10,7 +10,7 @@ static const char TAG[] = __FILE__;
 AXP20X_Class axp;
 
 void AXP192_init(void) {
-  
+
   if (axp.begin(Wire, AXP192_PRIMARY_ADDRESS))
     ESP_LOGI(TAG, "AXP192 PMU initialization failed");
   else {
@@ -49,16 +49,26 @@ esp_adc_cal_characteristics_t *adc_characs =
     (esp_adc_cal_characteristics_t *)calloc(
         1, sizeof(esp_adc_cal_characteristics_t));
 
+#ifndef BAT_MEASURE_ADC_UNIT // ADC1
 static const adc1_channel_t adc_channel = BAT_MEASURE_ADC;
+#else // ADC2
+static const adc2_channel_t adc_channel = BAT_MEASURE_ADC;
+#endif
 static const adc_atten_t atten = ADC_ATTEN_DB_11;
 static const adc_unit_t unit = ADC_UNIT_1;
-#endif
+
+#endif // BAT_MEASURE_ADC
 
 void calibrate_voltage(void) {
 #ifdef BAT_MEASURE_ADC
-  // configure ADC
+// configure ADC
+#ifndef BAT_MEASURE_ADC_UNIT // ADC1
   ESP_ERROR_CHECK(adc1_config_width(ADC_WIDTH_BIT_12));
   ESP_ERROR_CHECK(adc1_config_channel_atten(adc_channel, atten));
+#else // ADC2
+  // ESP_ERROR_CHECK(adc2_config_width(ADC_WIDTH_BIT_12));
+  ESP_ERROR_CHECK(adc2_config_channel_atten(adc_channel, atten));
+#endif
   // calibrate ADC
   esp_adc_cal_value_t val_type = esp_adc_cal_characterize(
       unit, atten, ADC_WIDTH_BIT_12, DEFAULT_VREF, adc_characs);
@@ -75,7 +85,6 @@ void calibrate_voltage(void) {
 #endif
 }
 
-
 uint8_t getBattLevel() {
   /*
   return values:
@@ -102,7 +111,6 @@ uint8_t getBattLevel() {
 
 // u1_t os_getBattLevel(void) { return getBattLevel(); };
 
-
 uint16_t read_voltage() {
 
   uint16_t voltage = 0;
@@ -114,17 +122,23 @@ uint16_t read_voltage() {
 #ifdef BAT_MEASURE_ADC
   // multisample ADC
   uint32_t adc_reading = 0;
+  int adc_buf = 0;
   for (int i = 0; i < NO_OF_SAMPLES; i++) {
+#ifndef BAT_MEASURE_ADC_UNIT // ADC1
     adc_reading += adc1_get_raw(adc_channel);
+#else                        // ADC2
+    ESP_ERROR_CHECK(adc2_get_raw(adc_channel, ADC_WIDTH_BIT_12, &adc_buf));
+    adc_reading += adc_buf;
+#endif
   }
   adc_reading /= NO_OF_SAMPLES;
   // Convert ADC reading to voltage in mV
   voltage = esp_adc_cal_raw_to_voltage(adc_reading, adc_characs);
-#endif
+#endif // BAT_MEASURE_ADC
 
 #ifdef BAT_VOLTAGE_DIVIDER
   voltage *= BAT_VOLTAGE_DIVIDER;
-#endif
+#endif // BAT_VOLTAGE_DIVIDER
 
 #endif // HAS_PMU