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Missing ADC_RDY

Michael Chan84
Prodigy 100 points
Other Parts Discussed in Thread: AFE4400

Hi,

I have configured the AFE4400 and the timer module (same as Table 2 on Pg 31). However, when I observed ADC_RDY, I did not see continuous pulses with the sampling rate of 500Hz. Instead, occasionally 10 ADC_RDY will appear then go missing for a while. I have seen one person posting this problem at the end of a thread (e2e.ti.com/.../418841). Thanks in advance for your help.

Regards,

Michael

  • 0
    TI__Mastermind 49906 points
    Hi Michael,

    You may find a resolution to your issue here:
    e2e.ti.com/.../1544396
  • 0 in reply to Praveen Aroul
    Prodigy 100 points
    Thank you for providing this link. I am observing the same thing they experienced. However, that problem didn't seem to be resolved. On my scope, I triggered the capture on ADC_RDY signal but did not see repetitive ADC_RDY pulses. Therefore, I am still not convinced this is a scope capturing issue. Is there any other way that proves it is?

    Regards,
    Michael
  • 0 in reply to Michael Chan84
    Prodigy 100 points

    I tried to verify that missing ADC_RDY is indeed not a scope issue. Therefore, I use Arduino to detect the period of the pulses using the following function:

     int value = pulseIn(SPIDRDY, LOW);

     Serial.println(value); 

    However, I see the following:

    9892
    2242
    2527
    2560
    4837
    14475
    29773
    14759
    2276
    12739
    2276
    7650
    2021
    37624
    2276
    7365
    12203
    2274
    22159

    Note that the unit is in microseconds. I'd be happy if I see consecutive 2xxx values. Nevertheless, I didn't, so I conclude that there is something other than the scope that causes missing ADC_RDY. Please help,

    Regards,

    Michael