[Bug]: Battery voltage measurement always gets an invalid first reading after reset

[dm5tt]

Category

Other

Hardware

Other

Firmware Version

2.5.11 and master

Description

Hardware: HT-CT62 (ESP32C3)

Looks like the first reading coming from the ADC is always invalid and then triggering the first shot of the low voltage battery warning.

My variant.h configuration

#define BATTERY_PIN 1
#define ADC_CHANNEL ADC1_GPIO1_CHANNEL
#define ADC_MULTIPLIER 2 * 1.02
#define BATTERY_SENSE_SAMPLES 5

Relevant log output

DEBUG | ??:??:?? 1 SX126X_RXEN not defined, defaulting to RADIOLIB_NC
DEBUG | ??:??:?? 1 SX126X_TXEN not defined, defaulting to RADIOLIB_NC
DEBUG | ??:??:?? 1 Use MCU pin -1 as RXEN and pin -1 as TXEN to control RF switching
INFO  | ??:??:?? 1 Set RX gain to boosted mode; result: 0
E (3381) gpio: gpio_isr_handler_remove(482): GPIO isr service is not installed, call gpio_install_isr_service() first
INFO  | ??:??:?? 1 SX1262 init success
INFO  | ??:??:?? 1 Not using WIFI
DEBUG | ??:??:?? 1 LoRA bitrate = 118.500000 bytes / sec
INFO  | ??:??:?? 1 PowerFSM init, USB power=1
DEBUG | ??:??:?? 1 State: BOOT
DEBUG | ??:??:?? 1 [Power] Battery: usbPower=0, isCharging=0, batMv=3100, batPct=0      <- Invalid first reading
DEBUG | ??:??:?? 1 [Power] Low voltage counter: 1/10
INFO  | ??:??:?? 1 [RangeTest] Range Test Module - Disabled
INFO  | ??:??:?? 4 [PowerFSM] Loss of power in Powered
INFO  | ??:??:?? 5 [PowerFSM] Loss of power in Powered
DEBUG | ??:??:?? 5 [PowerFSM] State: ON
INFO  | ??:??:?? 11 [EnvironmentTelemetry] Environment Telemetry: init
INFO  | ??:??:?? 11 [EnvironmentTelemetry] Init sensor: SHT31
[ 11659][W][Wire.cpp:301] begin(): Bus already started in Master Mode.
INFO  | ??:??:?? 11 [EnvironmentTelemetry] Opened SHT31 sensor on i2c bus
(...)
DEBUG | ??:??:?? 21 [Power] Battery: usbPower=0, isCharging=0, batMv=3963, batPct=77  <- Correct second reading.