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Original question:

ADS131A04EVM: I want to use a higher sample rate like the 64k Samples per second setting for sampling data on the input of...

ADS131A04EVM: Error data rate above 42,7kSPS

Inigo van de Locht
Prodigy 20 points
Part Number: ADS131A04EVM

Hello,

When I try to increase the data rate above 42,7kSPS I get the following error:

According to the error at such high rates, the software may not be able to properly communicate or deliver samples reliably.

I tried to set the data rate to 128kSPS and put CLK_DIV and ICLK_DIV to 2 and OSR to 32 to achieve the data rate of 128kSPS.

Does this mean the software is not suited for a data rate above 42,7kSPS?

Regards,

Inigo

  • 0
    TI__Guru 66466 points

    Hi Inigo,

    The EVM should be capable of supporting this, I'm not sure why this warning message is there. You can verify on a logic analyzer / scope that each SPI frame starts and ends between DRDYn falling edges, which indicates that the interface is running fast enough to read all the data without missing the next conversion. 

    Let me know if the data appears corrupted at the faster data rates and we can review it.

    Regards,

    Ryan

  • 0 in reply to Ryan Andrews
    Prodigy 20 points

    Hi Ryan,

    When I measure the DRDY I get the following image:

    I put the sampling frequency on 128kHz and according to the image the frequency of the DRDY is 133kHz.

    I think this means the data is not corrupted at a faster data rate.

    Regards,

    Inigo van de Locht

  • 0 in reply to Inigo van de Locht
    TI__Guru 66466 points

    Hi Inigo,

    We would have to analyze the ADC conversion data to determine whether there is a problem at higher data rates. The DRDYn interrupt only indicates when the device itself has completed a new conversions. This is not dependent on the software provided with the EVM. 

    However, I am wondering why the data rate is not exactly 128 kSPS when CLKIN = 16.384 MHz and the dividers are configured as you mentioned in your initial post. Maybe this is just a measurement issue on the scope? Ensure you are measuring the time between consecutive falling edges, not rising edges.

    Regards,

    Ryan