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ADS1299 DRDY IO occasionally appears with incorrect waveform.

user5083913
Prodigy 40 points
Part Number: ADS1299

At present, we have found a problem when debugging ADS1299. The DRDY pin waveform sometimes appears as follows, resulting in the failure of reading data:

1.DRDY lag time is too long, about 2ms;

2. DRDY has the backward situation, the normal is a lower after about 10 us up, this time with new data, abnormal, DRDY has kept a low level (2 ms) up (about 10 us), pull down again.Please see the screenshot below

DRDY is too long.

 DRDY wave is reversed.

So, I want to know, what are the conditions for DRDY to be affected?

Thanks.

  • 0
    TI__Guru 57296 points

    Hello,

    Welcome to our forum!

    The first SCLK falling edge forces /DRDY to clear and return high. Therefore, the pulse duration of /DRDY depends on when you read the data (please see Figure 41). If the device is in Continuous Conversion Mode and you do not read the data after /DRDY = low, then /DRDY will remain low until a few tCLK periods before the next sample is completed (see Figure 42).

    It is important that you finish reading all 216 bits per conversion (STATUS + 8 ch x 24 bits) before the next /DRDY falling edge to avoid data corruption.

    Best Regards,