ADC self calibration

[STaka.3]

​Hello,

I am using STM32L471QE.

​Please tell me how to calculate CALFACT_S and use it for ADC self calibration.

I confirm that ADC1_CALFACT in CALFACT_S is 0x3A or 0x3B.

I want to know how much [CALFACT_S] affects accuracy.

Please let me know if there is a document that explains ADC self calibration in detail.

I can't understand it to read reference manual.

Thanks.

[Imen.D]

Hello @STaka.3​ ,

Welcome to the STM32 Community =)

The ADC self calibration allows to cancel positive and negative offset (+/-64 LSB).

It's an offset calibration, it only corrects the offset error, and this is done automatically by the ADC when you launch a calibration.

Please double check in reference manual RM0351; this should be clear in section "18.4.8 Calibration (ADCAL, ADCALDIF, ADC_CALFACT)".

You can also review the AN2834 Application note How to get the best ADC accuracy in STM32 microcontrollers.

Imen

[STaka.3]

Hello Imen DAHMEN (ST Employee)

Thank you for your answer.

I read manual RM0351.

Add Can you tell us about the following.

How to calculate CALFACT_S ?​

​VREFINT×〇〇= CALFACT_S?

The sensor output of my product is adjusted at the factory.

And store the AD value of the sensor output in the MCU.

​I am worried that the ADC self calibration cause gap of store the AD value.

Shun