How do I configure +Vref for STM32WL boards?

[YO.1]

Hi team,

I am using LoRa-E5 dev board that uses STM32WLE5JC MCU.

I have been trying to implement ADC peripheral.

How do I configure the +Vref of the ADC? Is there any configuration parameter or API?

Thanks.

[Bubbles]

Hi @YO.1​,

I'm sorry but from the seeed studio documentation I'm unable to determine what's the VREF+ pin connected to on their board. Try asking them directly.

Alternatively you can use the method described in the RM chapter 16.9 to calculate the VREF+ using VREFint.

Most likely the board simply connects vref+, VDDA and VDD to the same power source. If it's a battery, it's actually not completely bad idea. You just have to use VREFint to see how much the battery level dropped before using it for actual ADC measurements.

BR,

J

[YO.1]

Thank You J. I shall refer to the chapter 16.9 as You suggested.