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ADS1299: Problem with getting the data and data rate

user4957792
Prodigy 130 points

Part Number: ADS1299

Hi there,

We've been using the ADS1299 with a DSP from STMicro and we're printing the data as we read it from the ADC. At 250 samples/s it works perfectly, but at 1k samples/s we're getting some spikes on the output. We suspect that the printing of the samples on the UART is somehow taking more time than it should and is trampling the timing of the DRDY signal, even though we're using it as an external interrupt. I've attached two pictures that show this problem.

Any ideas on how to fix the problem ?

Thanks,

Luis

  • 0
    TI__Guru 68916 points
    Hello Luis,

    Thanks for your post. Most likely this is an SPI timing issue. Try to monitor /DRDY, /CS, SCLK, and DOUT together and see if one of your data read transactions is overlapping a /DRDY interrupt. If you are in RDATAC mode, then the current data will be overwritten with new data each time a sample is ready.

    Best Regards,