POWER_ADC_NOTES.md

Power and ADC Notes

Date: 2026-05-04

ADC and power-path distinction

The current package distinguishes between three different concepts:

• normal external analog pins,
• a dedicated board VBAT pin that consumes one ADC-capable input,
• the nRF52 VDDHDIV5 internal measurement path.

Board-level battery models

• promicro_nrf52840: battery sense is modeled on public pin 29.
• nicenano_v2: battery sense is modeled through VDDHDIV5.
• supermini_nrf52840: battery sense is modeled through VDDHDIV5.
• nrfmicro_nrf52840: battery sense is modeled on VBAT.
• mini_nrf52840: battery sense is modeled on public pin 31.
• pitaya_go_nrf52840: battery sense is modeled on public pin 28.

Practical caveats

• When a board uses a public VBAT pin, that pin is no longer a free generic analog input in practical board usage.
• When a board uses VDDHDIV5, there is no dedicated public battery pin, but battery reads come from the internal divided supply path.