Cannot configure VREF on Nucleo-64 STM32G474RE

[TThai.1]

Hi,

Using STM32G474RE board (Nucleo-64). I have tried a lot of different things to configure VREFBUF and none of them have any effect.

I'm outputting two voltages on DAC1 at 75% scale and 25% scale and they are always relative to approx 3.25V (which is what I see on the VDDA pin). I wanted to see if I could observe e.g. DAC using VREF of 2.048v (or any of the configurable voltages).

I've tried setting the VRS, HIZ and ENVR bits directly and I've also tried the LL_VREFBUF_* calls. I have the SYS/VREFBUF Mode set to "Internal voltage reference" in the Device Configuration Tool. None has any effect. I am using the STM32CubeIDE.

In fact I would really like to configure this pin as external reference for my application but I can't achieve that either.

Any clues? Thanks.

[TThai.1 · Accepted solution]

OK, I was too focused on the header pins and completely forgot the VREF jumper JP8. Removing this jumper produces the expected result with VREFBUF voltage scale.

Leaving the question here in case anyone else makes a similar mistake.