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Visitor II
September 22, 2025
Solved

Maximum offset error of STM32C011 without ADC calibration

  • September 22, 2025
  • 1 reply
  • 167 views

Hello everybody,

in our application, we want to avoid using the ADC software calibration procedure (not even once).

We hence think about writing a fixed value to the Calibration register CALFACT as we saw that most of the times the calib value is very close to 64 (half of the 7-bit range).

We can accept a comparably high offset error of the ADC (+-12LSB at 12 bit) and from our measurements so far we think we can work without calibration, however we cannot find any worst-case offset values for the uncalibrated ADC anywhere. 

So our questions are:

Can you confirm that 64 is the somewhat "neutral" value for CALFACT?

Where can I find the worst case offset error of the ADC without calibration?

 

Best regards and thank you very much in advance

Samuel

    This topic has been closed for replies.
    Best answer by TDK

    The ADC is required to go through the calibration procedure in order for the accuracy specifications in the datasheet to be valid. The accuracy without calibration is not specified or guaranteed.

    You can manually set the calibration factors if you want. Perhaps calibrate once and then store them in flash.

    1 reply

    TDKAnswer
    Super User
    September 22, 2025

    The ADC is required to go through the calibration procedure in order for the accuracy specifications in the datasheet to be valid. The accuracy without calibration is not specified or guaranteed.

    You can manually set the calibration factors if you want. Perhaps calibrate once and then store them in flash.