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TMS320F280039C: ADC SOC question

sangmo kim
Prodigy 210 points
Part Number: TMS320F280039C

Tool/software:

Hi.

I use TMS320F280039C.

I have a question that ADC SOC operation.

I set ADC SOC below.

1. ADCA number 0, 1, 2, 3 - SOC trigger EPWM8, 300kHz

2. ADCA number 4, 5, 6, 7, 8 - SOC trigger EPWM1, 55kHz

    ADCB number 0, 1, 2, 3, 4, 5, 6, 7, 8 - SOC trigger EPWM1, 55kHz

    ADCC number 0, 1, 2, 3, 4, 5, 6, 7, 8 - SOC trigger EPWM1, 55kHz

Does the ADC operate as shown in the figure below?

Best Regards,

Sangmo kim.

  • 0
    TI__Mastermind 37820 points

    Hi Sangmo,

    The operation you described is an asynchronous operation where concurrent operation of ADCs where triggering is not done at the same time (55Khz and 300Khz trigger sources) will result in conversion coupling noise that will cause degraded results.  A proper solution would be to:

    1.) Use the same number of SOCs for all ADCs

    2.) Trigger all conversions from one source, the fastest probably which is300Khz

    3.) Ensure all ACQPs is the same length for all the SOCs

    Above will result in synchronous operation of the ADCs where sampling time and conversion time will be aligned at all times and no risk of coupling.  For SOCs that need to be sampled at slower rate, you can increase the SOCs used and only read the SOC result once.

    Regards,

    Joseph