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Problem in adi_AFE_TiaChanCal()

Question asked by amf on May 18, 2017
Latest reply on May 24, 2017 by amf

The ADuCM350's error correction (i.e. no factory calibration) seems to have a problem.  It gives very inconsistent results

when calibrating the TIA channel's gain correction.  Specifically, I'm running amperometric.c and applying a 0.6V step across a 4 Mohm load (RCAL and RTIA are also both 4 Mohms).  

 

I've narrowed the problem down to the call to adi_AFE_TiaChanCal() ... and specifically to these last few lines of that function (attached).  If you set a breakpoint and step through the lines of code shown, you get a very different answer every time for the value of channel_gain, which is what gets written to the TIA gain calibration register:  ADI_AFE_CAL_REG_ADC_GAIN_TIA.

 

Have you seen this problem before?  Do you know what the problem is?

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