STM32MP157C - ADC issues in Engineering Mode

[Steffen M]

Hello,
I am trying to read an analog value of PA4 of the STM32MP157CAC with ADC1 but it does not work.
I am using from Emtrion the emSTAMP-Argon as module.
I also tried to read the internal temperature sensor instead with ADC2 but that failed as well.

I do see AD_START to get cleared after being set; thus the basic ADC is working (at least that is my understanding). Nevertheless, I do not see any change of the ADC_DR register is always 0x8000.
The ADC_PCSEL is modified to enable the channels and ADC_SQR1 is also configure.
The ADC of STM32s are not new to me as I did use STM32F4, STM32F3 and STM32WB for some time. 

If I am switching from 16 bit to 12 bit e.g. I do see ADC_DR shifting. 

Any suggestions or hints would be great as I do not know what I am doing wrong.
I might be wrong but in engineering mode, there shouldn't be any issues with TF-A etc. possible or?

Thank you
Steffen

[Olivier GALLIEN]

Hi @Steffen M ,

Seems that  emSTAMP-Argon  has an embedded PMIC. 

Do you know wich PMIC supplies are wired to ADC VDDA and/or VREF and if they are turn-on in your case ? 

Pmic supplies are not managed in Engi mode except you add it to your application. 

If Emtrion does not provide drivers, refer to EVAL or DK BSP in our software delivery to get them 

Hope it help 

Olivier 

[Steffen M]

No I do not know this. Can I use the internal reference instead and ignore the external connection?

[Olivier GALLIEN]

Hi @Steffen M 

You have to provide either VDDA for VREFBUF or VREF+. 

Olivier