Kris Sielski

LPC824 ADC Offset

Discussion created by Kris Sielski on Mar 23, 2018
Latest reply on Sep 26, 2018 by Doug DeVries

I seem to be getting a large offset from the ADC on the LPC824.


I have the LPCXpresso824 eval board (OM13071) and I shorted the ADC input to GND.  I am using the default LPCopen ADC demo code.   The output of the ADC is 0x02C, which is about 35mV  [(3.3/4096)*44].  I have verified this on several different demo boards - all having an output value when the input is grounded.


I have verified that the calibration is being performed and have verified that the initialization and operation of the LPCopen code follows the users manual.


Am I doing something wrong or missing something that the ADC does not output zero when the input is grounded?


Thank you,