We are working with the ADC and we can read the registers over I2C. But the conversion of those values into voltages is a mystery to us and nowhere documented.

[inam]

If someone has that information please share, better would be if you can point me to the documentation where I can found the information.

We are using the STM32F429ZI nucleo board.

[Tesla DeLorean · Accepted solution]

An external I2C ADC? Which one?

The internal ADC?

If the board is running at 3V? voltageADC = 3.0 * measurementADC / 4096.0

[inam]

yes sorry, I meant the internal ADCs.

thank you for the quick response.

[KnarfB]

Internal ADC over I2C?

What code?

hth

KnarfB

[inam]

I applied the formula, and it works! We are using the I2C bus yes. Thank you Tesla

[KnarfB]

Maybe your MCU is running at 3.3V?

You can also measure Vdda by measuring the internal reference voltage Vrefint and extrapolate the result to get an estimate for Vdda. Details should be in the ref.man.

hth

KnarfB

[inam]

Thank you. I found my error and it works fine now. Accuracy is within 5 mV. Not ideal but acceptable.