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TMS320F2802 - ADC

Victor Gruzdyn
Prodigy 140 points
Other Parts Discussed in Thread: TMS320F2802

"The ADC of the TMS320F2802 is quite fast but you have to calibrate it. TI mentions that you have to perform a offset calibration during runtime. This is doable but there is not too much headroom for additional conversions. 
   
   do we need the calibration of the A/D or can we accept the higher TUE ? 
   do we actively have to issue this calibration or is this a background process done by the TI  DSP ?
   may we run this calibration during booting of the DSP ? "

Thank you,

Victor

  • 0
    TI__Guru 62975 points

    Victor,

    Calibration is optional.  Without running calibration, the ADC will be subject to the datasheet "Offset error" spec where trimming is not performed.

    According to this Application Report for F280x ADC Calibration, the process is to be executed by the application software.  I recommend that you also look at Chapter 8 "Gain and Offset Temperature Drift" which says:

    Once initial calibration values for gain and offset have been determined, CPU cycles can be saved by
    reusing these values, rather than calculating them every time an ADC conversion is performed. The
    frequency in which the application updates these values is determined by the stability of the input
    references, input drivers, and the ADC itself over temperature. This section allows you to determine how
    often, if at all, calibration values need to be updated based on gain and offset changes internal to the
    ADC.

    You should be able to execute the calibration once at boot unless otherwise needed.

    -Tommy