Battery pin definition non standard and untestable

[mitra42]

Board

Multiple - e.g. Lilygo T3S3

Device Description

None (attached to laptop, but not relevant)

Hardware Configuration

No

Version

latest stable Release (if not listed below)

Type

Task

IDE Name

PlatformIO

Operating System

N/A

Flash frequency

N/A

PSRAM enabled

yes

Upload speed

N/A

Description

The variant files contain at least 15 different ways of telling you on which pin the battery voltage can be measured.

Try grep BAT /Users/mitra/.platformio/packages/framework-arduinoespressif32/variants/*/pins_arduino.h
VBAT_VOLTAGE BAT_VOLTS BAT_VOLT BAT_MEASURE VBAT_SENSE BATT_ADC_PIN BAT_ADC_PIN BAT_ADC BATT_MONITOR BAT_MEASURE BAT_LV WS_BAT_ADC PIN_VBAT PIN_BATTERY BATTERY_PIN

What is worse is that these are mostly (though not all) static const uint8_t so it is next to impossible to write board independent (library) code without testing by board name

I am sure there is code that depends on most of these different definitions, so I would suggest we pick one and progressively add #defines to all variant files that define one common value.

I don't particularly care which is used but suggest it indicates its an ADC as for example VBAT_VOLTAGE could imply its the voltage level, so if we chose VBAT_BUILTIN

then e.g. on lilygo_t3_s3_sx1262/pins_arduino.h we could add #define VBAT_BUILTIN BAT_VOLT

I'm sure someone could write a quick python script to make all the changes, but I don't want to submit this as a PR if there is likely to be (reasonable) pushback.

Sketch

#ifdef ARDUINO_LILYGO_T3_S3_V1_X
  analogRead(BAT_VOLT); // Specific to a few boards
#elif defined(xxxxx)
  analogRead(VBAT_SENSE)
#elif ... repeat for every board that has built in battery measurement
#endif

Debug Message

n/a

Other Steps to Reproduce

No response

I have checked existing issues, online documentation and the Troubleshooting Guide

• I confirm I have checked existing issues, online documentation and Troubleshooting guide.

[lbernstone]

If the mfr has the pin labeled with specific text, the variant file should match.

[mitra42]

If the mfr has the pin labeled with specific text, the variant file should match.

I dont think I've seen a battery pin labeled. On the T3S3 for example it doesn't even come to a connector, its purely internal - from chip to V-bat. Code can find and read it, but there is no external pin.

As I understand it, a big part of the variant file is about allowing for libraries to work transparantly
across different boards. For example there are about 1000 variants that define either LED_BUILTIN or BUILTIN_LED, so my library can work with the LED on any of those boards. There are 400 variants that define MISO MOSI SCK so I can use SPI with them; similarly for SDA/SCL for I2C. But there is no commanlity for battery measurement despite 66 variants defining some version of it.

And ... as I pointed out in the first comment, there is really no way to handle this since you can't even put a massive #if #elif without naming every single board, since the definitions are in almost all cases static const rather than #define

[me-no-dev]

The battery pin is not something "standard" to Arduino, so variant submitters define it the way they want. You can make a define based code like

#ifdef ARDUINO_LILYGO_T3_S3_V1_X
  #define BAT_VOLT_PIN BAT_VOLT
#elif defined(xxxxx)
  #define BAT_VOLT_PIN VBAT_SENSE
#elif ... repeat for every board that has built in battery measurement
#endif

Or add the define in the variants files and submit a PR

[mitra42]

OK - done - and PR created, the changes were made programatically and then checked by hand, I can redo them if there is some difference (e.g. something other than BAT_VOLT_PIN) prefered.