• State TI Thinks Resolved
  • Locked Locked
  • Replies 7 replies
  • Answers 2 answers
  • Subscribers 82 subscribers
  • Views 1534 views
  • Users 0 members are here
Support feedback
Options
Options

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.

CCS/TMS320F28379D: Achieving Maximum Sampling Rate

Ajay Suresh
Prodigy 190 points
Part Number: TMS320F28379D
Other Parts Discussed in Thread: C2000WARE

Tool/software: Code Composer Studio

Hi,

I'm new to using the TMS320 Family of MCUs. I want to sample signals at the maximum possible sampling rate on a single channel (3.5 MSPS). Which example do I use, and how do I configure it? I've been trying to work with the adc_soc_epwm_cpu01 example, but it doesn't seem to be operating at the maximum frequency and I'm unable to figure out what the system's sampling frequency is? My graphs are pretty distorted.

  • 0
    TI__Genius 10845 points

    Hi,

    You need to configure the trigger frequency(pwm frequency) as per the desired frequency.

    Thanks

    Vasudha

  • 0 in reply to Vasudha Bhadoria
    Prodigy 190 points

    Hello,

    Thank you for your reply. That's what I've been trying to do by setting the TBPRD. Although, I'm not sure what the system's clock is sampling at, and what is the minimum value I can set the TBPRD to. Anything below 2800, and I'm unable to even read any samples. Would you know why that is?

    Best,

    Ajay

  • 0 in reply to Ajay Suresh
    TI__Genius 10845 points

    Hi,

    Are you able to run successfully the C2000Ware example mentioned above? Please refer to EPWM chapter in TRM for details on configuring EPWM registers for desired frequency.

    Thanks

    Vasudha

  • 0 in reply to Vasudha Bhadoria
    Prodigy 190 points

    Yes, I'm able to program the EPWM frequency to about 7 MHz (checked using GPIO Pins), but while monitoring the buffer, I'm still getting distorted images for frequencies as low as 1 kHz. Is the ADC sampling with a different clock, or is continuously writing to memory distorting the graphs? I want to be able to sample any signal with frequencies up to 2 MHz.  

  • 0 in reply to Ajay Suresh
    TI__Genius 10845 points

    Hi,

    yes I think EPWM frequency is too high for ADC trigger. The time between two triggers should be atleast equal to the end of conversion time for configured SOCs to get correct result.

    One approach could be to trigger 16 SOCs for same channel and trigger all the SOCs through same EPWM configured to trigger after 16 SOCs finish conversion.

    Thanks

    Vasudha

  • 0 in reply to Vasudha Bhadoria
    Prodigy 190 points

    Hello,

    So it looks like what I've set up should display continuous data. When I run it once, I don't have a problem. Yet, when I run it continuously, the graphing tool makes it look distorted. Is the data being transmitted from the MCU to the CCS Output not fast enough for the ADC? I am definitely not seeing the right graph and I've double checked my code multiple times. I feel that the graphing feature is giving me issues.

  • 0 in reply to Ajay Suresh
    TI__Genius 10845 points

    Hi,

    Were you able to resolve this issue?

    Thanks

    Vasudha