After calibration Primary / Auxiliary Channel ADC Offset Calibration Register (ADC0OF, ADC1OF) always are read = 0. Both self-offset and zero-scale calibration mode. It is unclear how to correct the values for negative/positive offsets.
ADUC7061
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The ADuC7060/ADuC7061 are fully integrated, 8 kSPS, 24-bit data acquisition systems incorporating high performance multi-channel sigma-delta (S-?) analog...
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ADUC7061 on Analog.com
After calibration Primary / Auxiliary Channel ADC Offset Calibration Register (ADC0OF, ADC1OF) always are read = 0. Both self-offset and zero-scale calibration mode. It is unclear how to correct the values for negative/positive offsets.
Hi,
I saw that you attached an image, but it's not loading on my end.
Have you checked the offset calibration register before initiating the calibration? Is the reading 0 as well?
The ADC offset calibration register is automatically applied to the ADC reading to compensate for the offset error.
Regards,
Karl
Before initiating the calibration value of registers ADC0OF, ADC1OF is about 2..8.
Before initiating the calibration value of registers ADC0OF, ADC1OF is about 2..8.
What is the configuration for the ADCFLT register? Is chopping enabled?
Yes, of course:
ADCFLT_CHOP_ENABLE | ADCFLT_RUNNING_AVERAGE | ADCFLT_NOTCH2
+
SF=9, AF=63 (Data_Rate=12.12Hz, Settling_Time=165ms, 50Hz --> -329dB)
Chopping already corrects the offset error. That is why the offset calibration register (ADC0OF, ADC1OF) reads as 0 after initiating the calibration since the chopping is enabled.