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ADS1299: Error occurs after running for a while

Cherry Zhou
Mastermind 22235 points
Part Number: ADS1299

The ten ADS1299 devices are daisy-chained, and the square wave signal generated internally by the ADS1299 is correct after power up, but problems occur after a period of operation.

After viewing with the logic analyzer, please see the following figure:

The customer would like to know what's the possible reason for that. 

Thanks a lot.

Best Regards,

Cherry Zhou

  • 0
    TI__Genius 11550 points

    Hi Cherry,

    Thanks for the post.

    It is not clear to me what may be the cause of the issue from the attached waveform. Are they seeing issue with DRDY or data corruption when the error occurs? Is the issue happen consistently after device power-up? It may be caused by corruption in the SPI bus. Can they issue a RESET command or toggle the RESET pin when the error occurs? 

    Thanks

    -TC

  • 0 in reply to TCT
    TI__Mastermind 22235 points

    Hi TC,

    Thanks for your reply.

    When the error occurs, DRDY is good, and some of data are corrupted. 

    Yes, it does happen consistently after device power-up.

    The customer uses continuous reading, and when the error occurs NO RESET is performed.

    Thanks and expecting the updates.

    Best Regards,

    Cherry

  • 0 in reply to Cherry Zhou
    TI__Genius 11550 points

    Hi Cherry,

    Thanks for the information.

    It may be helpful to use the internal test signals to check the hardware signal chain and the software implementation in order to isolate the issue. Please verify that all the timing requirement is met for the daisy-chain devices. You can also probe the SPI bus for each individual device to see if there is any issue with any particular device in the daisy chain.

    Thanks

    -TC

  • 0 in reply to TCT
    TI__Mastermind 22235 points

    Hi TC,

    Thanks for your reply and suggestions!

    After the customer changed the continuous sample mode to a single sample, SCLK could not pull up the DRDY.

    The customer would like to know what's the possible reason for that.

    Thanks again!

    Best Regards,

    Cherry

  • 0 in reply to Cherry Zhou
    TI__Genius 11550 points

    Hi Cherry,

    Thanks for the support.

    In Single-Shot mode, the DRDY will remain low after a single conversion is completed regardless of whether the conversion data are read or not. Therefore, to begin a new conversion, either take the START pin low and then back high or send the START command again. Please refer to Section 9.4.6 in the datasheet for the Single-Shot mode operation.

    Thanks

    -TC