1 files changed, 41 insertions, 18 deletions

diff --git a/src/drivers/battery.cpp b/src/drivers/battery.cpp
index b3341eab..b45e20cf 100644
--- a/src/drivers/battery.cpp
+++ b/src/drivers/battery.cpp
@@ -1,31 +1,54 @@
 #include "battery.hpp"
+#include <cstdint>
 
-#include "driver/adc.h"
-#include "esp_adc_cal.h"
+#include "esp_adc/adc_oneshot.h"
 #include "hal/adc_types.h"
 
 namespace drivers {
 
-static esp_adc_cal_characteristics_t calibration;
-
-esp_err_t init_adc(void) {
-  // Calibration should already be fused into the chip from the factory, so
-  // we should only need to read it back out again.
-  esp_adc_cal_characterize(ADC_UNIT_1, ADC_ATTEN_DB_11, ADC_WIDTH_BIT_12, 0,
-                           &calibration);
-
-  // Max battery voltage should be a little over 2V due to our divider, so
-  // we need the max attenuation to properly handle the full range.
-  adc1_config_width(ADC_WIDTH_BIT_12);
-  adc1_config_channel_atten(ADC1_CHANNEL_6, ADC_ATTEN_DB_11);
+static const uint8_t kAdcBitWidth = ADC_BITWIDTH_12;
+static const uint8_t kAdcUnit = ADC_UNIT_1;
+// Max battery voltage should be a little over 2V due to our divider, so we need
+// the max attenuation to properly handle the full range.
+static const uint8_t kAdcAttenuation = ADC_ATTEN_DB_11;
+// Corresponds to GPIO 34.
+static const uint8_t kAdcChannel = ADC_CHANNEL_6;
+
+Battery::Battery() {
+  adc_oneshot_unit_init_cfg_t unit_config = {
+    .unit_id = kAdcUnit,
+  };
+  ESP_ERROR_CHECK(adc_oneshot_new_unit(&unit_config, &adc_handle_));
+
+  adc_oneshot_chan_cfg_t channel_config = {
+    .bitwidth = kAdcBitWidth,
+    .atten = kAdcAttenuation,
+  };
+  ESP_ERROR_CHECK(adc_oneshot_config_channel(adc_handle_, kAdcChannel, &channel_config));
+  
+  // calibrate
+  // TODO: compile-time assert our scheme is available
+  adc_cali_line_fitting_config_t calibration_config = {
+    .unit_id = kAdcUnit,
+    .atten = kAdcAttenuation,
+    .bitwidth = kAdcBitWidth,
+  };
+  ESP_ERROR_CHECK(adc_cali_create_scheme_line_fitting(&calibration_config, &adc_calibration_handle_));
+}
 
-  return ESP_OK;
+Battery::~Battery() {
+  adc_cali_delete_scheme_line_fitting(adc_calibration_handle_);
 }
 
-uint32_t read_battery_voltage(void) {
+auto Battery::Millivolts() -> uint32_t {
   // GPIO 34
-  int raw = adc1_get_raw(ADC1_CHANNEL_6);
-  return esp_adc_cal_raw_to_voltage(raw, &calibration);
+  int raw;
+  ESP_ERROR_CHECK(adc_oneshot_read(adc_handle, kAdcChannel &raw));
+
+  int voltage;
+  ESP_ERROR_CHECK(adc_cali_raw_to_voltage(adc_calibration_handle, raw, &voltage));
+
+  return voltage;
 }
 
 }  // namespace drivers