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ADIS16364 read problem

Category: Hardware
Product Number: ADIS16364

Hello,

I have two ADIS16364 IMUs

Read gyroscope and acceleration data with NI sbRIO-9629 FPGA by SPI

But 2 IMU gave different results as shown below

First ADIS16364

First ADIS16364

Second ADIS16364

Second ADIS16364

Sample rate was 500 Samples/sec

Second IMU would give the same data several times(about 9~10 times)

Would any settings or hardware issues lead to this result?

thank you,

randyko26

  • Hello randyko26,

    The ADIS16364 SMPL_PRD register allows for configuration of the IMU sample rate. If your FPGA is reading SPI data asynchronous to the data ready signal, it may be possible that the IMU sample rate has been inadvertently set to sample 9-10x slower than desired. I would recommend explicitly writing this register to the desired setting during IMU configuration (SMPL_PRD = 0x0000 for max rate sampling).

    If that does not resolve the issue, can you measure the data ready signal frequency, and check that it matches the expected sample rate (819.2Hz)?

    Thank you for the inquiry,

    Alex Nolan

  • Hello Nolan,

    Thank you for your reply

    I had doubt register SMPL_PRD caused this problem first.

    But the FPGA SPI process did not set SMPL_PRD register ever.

    And the SMPL_PRD is not a flash backup setting, so I did not try it before.

    I'll try this later.

    But I have another question that I could not read the PROD_ID from this IMU

    And the other register was the same, the picture was the signal when I communicated with ADIS16364

    Clock rate is 1MHz

    Would any settings or hardware issues lead to this result?

    Thank you

    Randyko26