I am looking to determine from software what supply voltage the B524 sees, that is Vcc and or V3.3.
The reference state B SOM devices have a fuel gauge Battery Voltage | Reference | Particle, but I am thinking that is actually on the evaluation board?
If so, are there other options on the B524 itself?
The 3V3 supply powers the nRF52840 MCU. The VCC (3V7) supply is only connected to the cellular modem.
The B524 doesn’t have an onboard PMIC, the software reference applies if you are using the evaluation board or have added a bq24195 to your base board.
Incidentally, there is no way to determine the actual supply voltage value, even with a bq24195. There’s no ADC connected to the supply; the voltage cut-offs work because the bq24195 uses DACs and comparators, not a digital value comparison.
I found that the EG91 supply voltage Vbat can be read with AT+CBC. I am not sure how accurate it is.