enable battery monitoring on HeltecV2

include/power.h

@@ -2,8 +2,8 @@
 #define _POWER_H
 
 #include <Arduino.h>
-#include <driver/adc.h>
 #include <esp_adc_cal.h>
+//#include <esp32-hal-adc.h>
 
 #include "i2c.h"
 #include "reset.h"
@@ -43,6 +43,11 @@
 #endif
 #endif
 
+#ifdef BAT_MEASURE_ADC_UNIT // ADC2 wifi bug workaround
+extern RTC_NOINIT_ATTR uint64_t RTC_reg_b;
+#include "soc/sens_reg.h" // needed for adc pin reset
+#endif
+
 typedef uint8_t (*mapFn_t)(uint16_t, uint16_t, uint16_t);
 
 uint16_t read_voltage(void);