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ADS127L18EVM-PDK: ADS127L18

HAO LI
Prodigy 10 points
Part Number: ADS127L18EVM-PDK

When I was performing register read and write operations, the registers accessed did not match the ones written to, and the data accessed would change.

The waveform indicates a write address of 0x11 and the content is 0x53.

However, the data read was 0x56 and 0x00.

And when writing to 0x42/0x4A, errors may sometimes occur.

  • 0
    TI__Mastermind 24295 points

    已经收到了您的案例，调查需要些时间，感谢您的耐心等待。

  • 0
    TI__Mastermind 30300 points

    Can you provide the your name and project information 

    Is this a custom board, or is this the ADS127L18EVM board?  Are you using the EVM GUI software, or is this connected to a different controller?

  • 0 回复 Links
    Prodigy 10 points

    It was using the EVM board, but the controller did not use the corresponding controller. Instead, it was a self-developed FPGA board.

    I used USB 3.0 to communicate with the FPGA board and used the SPI module to control the ADC chip. This module was written by myself.

    Most of the address reads and writes are fine, but sometimes the CHn_CFG1 and CHn_CFG2 registers may have errors when being read or written.

    This may sound a bit weird.

  • 0 回复 HAO LI
    TI__Mastermind 30300 points

    Hi

    Sorry for the delayed response, but I have been out of office for the past week, and this thread had accidentally been closed.

    This is likely a signal integrity issue.

    Please confirm the SCLK frequency used.  The maximum allowed is 13.3MHz.  In order to allow for settling time, I suggest using an SCLK frequency less than 10MHz.  Also, the interface logic is 1.8V only.  Please confirm with the customer they are using 1.8V CMOS levels for the SPI port.

    The frame following the WRITE operation (2nd SPI frame) should echo the data written to the register, or 0x53h.  Since this frame is a read register, the next frame (3rd SPI frame) should also read 0x53h.

    Regards,
    Links

  • +1 回复 Links
    Prodigy 10 points

    Thank you for your reply, this is very helpful to me.I did indeed detect ringing on the SCLK, by modifying the connection method, this phenomenon has been reduced. Now the data can be read and written correctly.

    Additionally, I would like to clarify why the SCLK measured on the official control board EVM is 16M?

  • +1 回复 HAO LI
    TI__Mastermind 30300 points

    For a new question, please re-submit a new ticket.