This thread has been locked.

If you have a related question, please click the "Ask a related question" button in the top right corner. The newly created question will be automatically linked to this question.

Where is the documentation for Piccolo TMS320F2805x calibration data OTP for the PGA compensation?

Other Parts Discussed in Thread: CONTROLSUITE

Where is the documentation for the location and proper use of the calibration data for PGA compensation?

I found an example for PGA compensation in controlSUITE, it defines a location in the calibration data OTP for PGA offset correction as:

#define PGA_COMP_LOC     0x3D7E61

I have found no other documentation about this compensation, the example is rather poorly documented regarding the gain compensation for the PGA (are different compensation values used for each PGA?  Where ares these values located?  What is their proper usage?).  The only other reference to PGA compensation I found was a brief blurb in a heading in the datasheet (table 6-44 p.93) http://www.ti.com/lit/gpn/tms320f28052f.

Any help here would be appreciated.

Thanks,

Mark

  • Mark,

    That is a blind spot in the documentation at the moment. However, the controlSUITE example that you referenced should provide a working understanding of the compensation scheme while we get the docs updated with more details.

    To use the compensation, you simply need to make the PgaComp() function call using your own input parameters according to the values defined in F2805x_Pga_defines.h.

    The short explanation for how it works is that there are unique gain and offset compensation terms for each PGA channel and each gain mode. The compensation terms are stored in OTP at location 0x3D7E61.

    The terms alternate in OTP like:

    CH1 OFFSET (int16)
    CH1 GAIN (Q14)
    CH2 OFFSET (int16)
    CH2 GAIN (Q14)

    The compensation is a simple "y = Gx - O" scheme where "y" is compensated and "x" is original.

    -Tommy