STM32C071GBU6 ADC Question

[ToddGilbert32]

STM32C071GBU6 PA2 (pin 8 on the UFQFPN28 device) is configured as ADC_IN2.  What voltage can be expected when the pin is unloaded?

[Peter BENSCH]

Welcome @ToddGilbert32, to the community!

Well - if the pin is initialised as ADC_IN2 and nothing is connected to it, the pin floats and no defined voltage is to be expected there.

Does it answer your question ?

Regards
/Peter

[ToddGilbert32]

Thanks Peter.  I should have provided this information - the pin is reading 28mV.  Is this to be expected?

[Peter BENSCH · Accepted solution]

If by ‘the pin is reading’ you mean the ADC attempting to measure a voltage on this floating pin, then the result is unpredictable. Floating input pins, whether digital or analogue, always exhibit this behaviour. The designer of the system is responsible for ensuring that such a condition does not occur or is handled appropriately.

Regards
/Peter

[gbm]

Any voltage between 0 V and Vdd might be expected.

[ToddGilbert32]

Thanks Peter! :)

[ToddGilbert32]

Thanks gbm! :)