vref voltage of stm32f429 disc1

[harry123]

Hello all. I am working with internal ADC can I know what is the internal reference voltage and how to change the internal reference voltage? 

[Peter BENSCH]

You can find this information in the STM32F429ZI data sheet, section 6.3.24:

VREFINT (Internal reference voltage) = min 1.18V, typ 1.21V, max 1.24V

You cannot change it, but you could apply an external reference voltage to VREF+ (pin 32) if you first desolder R58, which connects VREF+ to VDD.

Hope that helps?

Regards
/Peter

[harry123]

Thank you ...but there is an option to change VDD in cubemx tried it but the result looks the same.

[Peter BENSCH]

> but there is an option to change VDD in cubemx

Do you mean VDD in the RCC, System Parameters block?

This has no effect on a reference voltage, but on a #define VDD_VALUE, for example, which can be used for ratiometric measurements, among other things. A reference voltage is generally independent of the supply voltage - otherwise it would not be a reference, would it?

[waclawek.jan]

> but there is an option to change VDD in cubemx

Where exactly?

JW