I'm using AD7193 and i'm performing an internal zero-scale & full-scale calibration. Upon calibration, AD7193 goes to idle state. When i read the calibrated values from the offset and full scale register, the values are different from factory calibrated values which indicates that the calibrated values are programmed into the EEPROM.
But the problem is, when i do a reset by issuing continuous 1's for 40 clock cycles (or) when the device is power cycled and i try to read back the offset and full scale registers, I only see the factory programmed values and not the values that i calibrated in the above steps. As per the datasheet, internal/system calibration will overwrite the factory calibrated values but it seems to be not retained in the EEPROM. Is this an expected behavior?
Does it not retain the values? why?
If so, does an internal/system calibration has to be performed after every power up / reset?