Hello.
I am experiencing a very strange behaviour in an ADC built into one of ST's SOCs. I have verified it several times, all the registers are configured correctly. When I connect the input line to a known-voltage node, the outputs are within acceptable tolerances. However, when I connect the input to an analog sensor, the ADC starts behaving weirdly. And, as soon as I probe the ADC's anti-aliasing cap, either through an oscilloscope or through a simple male-to-male header, the ADC readings get back on track. I have tested the sensor in a standalone setup, the sensor is working fine. I even have several of the same sensor, which I did test with this ADC setup, but the ADCs isn't responding any differently for any of them. I even have multiple of those ADC boards, and even changing them does not help.
I have no clue what might be causing the ADC to give such erroneous values for the sensor input when it is working correctly for fixed voltages, or, why the ADC starts working fine when the input line is probed!
It would be nice if anyone could help me in solving this mystery.
I am experiencing a very strange behaviour in an ADC built into one of ST's SOCs. I have verified it several times, all the registers are configured correctly. When I connect the input line to a known-voltage node, the outputs are within acceptable tolerances. However, when I connect the input to an analog sensor, the ADC starts behaving weirdly. And, as soon as I probe the ADC's anti-aliasing cap, either through an oscilloscope or through a simple male-to-male header, the ADC readings get back on track. I have tested the sensor in a standalone setup, the sensor is working fine. I even have several of the same sensor, which I did test with this ADC setup, but the ADCs isn't responding any differently for any of them. I even have multiple of those ADC boards, and even changing them does not help.
I have no clue what might be causing the ADC to give such erroneous values for the sensor input when it is working correctly for fixed voltages, or, why the ADC starts working fine when the input line is probed!
It would be nice if anyone could help me in solving this mystery.
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