• State
  • Locked Locked
  • Replies 1 reply
  • Subscribers 81 subscribers
  • Views 418 views
  • Users 0 members are here
Support feedback
Options
Options
Related

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.

F2806x ADC Calibration problem

Monica Zolog
Expert 1905 points

Hi,

I have the folowing problem. I need to calibrate the ADC and all I can find about the ADCREFTRIM settings is in F2806x_Adc.h:

struct ADCREFTRIM_BITS {     // bits description
    Uint16    BG_FINE_TRIM:5;            // 4:0    Course Trim for Internal BG
    Uint16    BG_COARSE_TRIM:4;        // 8:5    Fine Trim for Internal BG
    Uint16    EXTREF_FINE_TRIM:5;        // 13:9    Fine Trim for External Reference
    Uint16    rsvd1:2;                // 15:14    Reserved
};


How should I calculate the values I must write in ADCREFTRIM? And do I only have to change them in F2806x_Adc.h?

I've tried to measure 3.3V with 2 different Piccolo control cards. With one I read 3.2 and with the other one 3.1. They both have ADCREFTRIM = 0x15AA.

Do I have to calibrate each control card in order to be sure the measurement is correct over the complete range?

Thank you,

Monica

  • 0
    TI__Genius 17101 points

    Monica,

      I took the liberty to split your post to a new thread since the original post was so old.

      For TMS devices, there is no need for to perform calibration to meet the datasheet specs.  Each device is given custom trims in the factory to ensure performance.

      If you silicon is TMX it will likely have a static trim value, in other words, all TMX devices get a common trim that should perform reasonably well, but is not guaranteed to meet datasheet specs.

      Here is another thread that discusses that a bit more

    http://e2e.ti.com/support/microcontrollers/c2000/f/171/p/295877/1031513.aspx#1031513

     

      If you do in fact have TMS silicon, be sure to respond so we can help further with the debug.

     

    Regards,

    Joe