offset and linearity calibration
Hello,
I'm working with the offset and linearity calibration on an STMH755. My board will run the full calibration at production, save off the resulting offset and linearity calibration constants, and then retrieve and apply them at any new restarts of the processor. I use the HAL and LL calls to first read them, for saving to NVRAM, then recalling and writing them at startup. To confirm these were in fact being installed on the ADC at startup, I ran a test where all offset and linearity calibration constants were intentionally set to 0. I would have assumed that would result in a 0 ADC readings, always (setting offsets and linearity constants to 0), but yet I am seeing non-zero values consistently.
Have I misunderstood something? I don't see much explanation of the actual applied calibration logic in any reference manuals or documentation read so far.
Please advise,
Robert