I have got 3 identical boards with STM32u5a5. For improving ADC accuracy I want to calibrate Vref using Vrefint. This is working fine on one board, but on the other two boards Vrefint reads as 0 using the same software. Other ADC channels seem to work on all boards.
Vrefint has been enabled and a delay has been added giving Vrefint time to settle.
On the working device I get ADC values around 24600 for Vrefint (left aligned), on the non-working devices exactly 0.
Since everything is working fine on one device, I wonder what could be the issue on the other two devices.
