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ADS127L01EVM: Capture enough data to perform FFT

Richard Tresidder
Prodigy 40 points
Part Number: ADS127L01EVM

Hi Trying to get the DAC Evaluation software to capture and export enough data to perform an FFT on..

Currently I only seem to be able to get it to collect 64k samples.!?

Kind of makes it utterly useless given its a 500ksps ADC

Am I missing something? Is there any way to do this via the USB interface? Or do I have to hack into the direct interface and generate some HDL in our FPGA to do this.. which will be time consuming for a test.

Was kind of hoping to perform some analysis of some frontends and this device prior to it actually going onto a PCB..

Regards

   Richard

  • 0
    TI__Guru 57296 points
    Hi Richard,

    Thanks for your post!

    We were limited to 64k points due to the TIVA microcontroller on our EVM platform. At 500kSPS, this would still give you a frequency resolution of 7.8125 Hz. However, since we cannot support coherent sampling with the EVM anyway, we expect that any signal leakage will be greater than than the frequency resolution, so we did not think acquiring more points would provide any benefit.

    What is the reason that you wish to acquire more than 64k points? You can still flywire into the EVM and collect more data with an external processor. The on-board TIVA microcontroller can be held in power-down using JP1.

    Best Regards,
  • 0 in reply to Ryan Andrews
    Prodigy 40 points

    Hi Ryan

       Yep my actual requirement was to actually test a sensor setup with this ADC prior to making a full board.
    Would've like to record some longer time series for analysis.
    We're also very interested in DC stability/noise, hence wanting more data to look at lower frequencies. No problems with the higher frequencies all seems pretty flat...

    I see now after reading in detail the 4.3.4 section of sbau261b.pdf there is a table with shows COLLECT command 0 to 64000...sigh..
    Thought I could take a bit of a shortcut for an investigation phase..

    I'll just have to rig something up to tie into our existing platform.

    Regards
       Richard