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SK-AM62: Connection confirmation for SPI via expansion connector

Ryuuichi machida
Guru 12650 points
Part Number: SK-AM62

Hello,

I would like you to confirm whether you have confirmed about below or not.

* According to schematic of SK-AM62, there is no device which can be controled by McSPI on SK-AM62.
To confirm McSPI function, user need to connect certain device to EVM via expansion connector ("J3" connector of EVM).
Then I have following question.

Q, Have you ever had any experience which you connect something SPI device via expansion connector("J3" connector) to confirm behavior of McSPI function on SK-AM62 under linux ?
If answer is yes, could you please tell me which device(parts number) you have connected ?

Best Regards,


  • 0
    TI__Guru 69642 points

    Hi Ryuuichi-san,

    I'm not aware what others/other teams might have tried, but it shouldn't be too difficult to get SPI communication to work, if you have all of the following:

    1. Proper driver for the device you want to connect is enabled in the Kernel
    2. Proper device tree setup for the SPI interface to be used, and the external device as needed with all of the following:
      1. Correct pinmux to match whatever pins you want for use for example from the J3 connector (can easily create the needed DTS code section using https://www.ti.com/tool/SYSCONFIG)
      2. Correct AM62x SPI peripheral setup 
      3. Correct SPI device setup

    For (b) and (c) one can usually get some inspiration from other DTS files that are in the Kernel tree by just searching.

    Also, this E2E post here provides essentially a working example based on the SPIDEV driver :
    https://e2e.ti.com/support/processors-group/processors/f/processors-forum/1122795/sk-am62-accessing-spi-onto-sk-am62-board-from-linux

    Regards, Andreas

  • 0 in reply to Andreas Dannenberg
    Guru 12650 points

    Hello Andreas-san,

    Thank you for your reply.

    I have already checked following thread which you attached.
    https://e2e.ti.com/support/processors-group/processors/f/processors-forum/1122795/sk-am62-accessing-spi-onto-sk-am62-board-from-linux

    However, there is no information how he realized SPI communication(we do not know connection composition(slave device information))

    Q1, Could you please tell me how to work SPI test application ?
    (I want to know physical connection to slave device)
    Q2, Is it possible to confirm about more detail for below internally ?
    >I'm not aware what others/other teams might have tried

    BR,

  • 0 in reply to Ryuuichi machida
    TI__Guru 69642 points

    Hi Ryuuichi-san,

    the post discussed somewhere how the SPI test demo part of the Kernel was used, it's located at tools/spi/spidev_test.c in the Kernel tree. You can simply cross-compile this application and copy it to the target device.

    If you are looking for something specifically tailored for SK-AM62, I'm not aware of something like a detailed tutorial what you seem to be looking for. But I can spend some time next week to search a bit more.

    Regards, Andreas

  • 0 in reply to Andreas Dannenberg
    Guru 12650 points

    Hello,

    Thank you for your reply.
    >the post discussed somewhere how the SPI test demo part of the Kernel was used, it's located at tools/spi/spidev_test.c in the Kernel tree. You can >simply cross-compile this application and copy it to the target device.
    I'm sorry what I would like you to ask is whether user need to prepare slave device to connect master device of SK-AM62 to confirm function of "spidev_test".
    Could you please give your answer from view point above ?

    >But I can spend some time next week to search a bit more.
    I also expect answer for above.

    Best Regards,

  • 0 in reply to Ryuuichi machida
    TI__Guru 69642 points
    Ryuuichi machida said:
    I'm sorry what I would like you to ask is whether user need to prepare slave device to connect master device of SK-AM62 to confirm function of "spidev_test".
    Could you please give your answer from view point above ?

    You can check/verify basic operation without connecting an actual slave device as follows:

    1. You could connect a logic analyzer to the SPI pins, and observe the toggling of the chipselect, clock, and data signals, and this way observing/verifying transmit behavior, and/or
    2. Connect the SPI output signal to the input signal with a jumper wire, this way creating an external loopback connection. When now sending data to the SPI device, you should receive the same data back. This will help verifying proper pinmux settings etc. (also in combination with 1 above)

    Regards, Andreas

  • 0 in reply to Andreas Dannenberg
    Guru 12650 points

    Hello Andreas-san,

    Thank you for your reply.
    From your reply, I understood as shown below.

    * By generating loopback configuration, user can confirm both "transmit" and "receive" function of SPI.

    If you get actual example internally, it is also helpful. So, please let me know if you get update.

    BR,

  • 0 in reply to Ryuuichi machida
    TI__Guru 69642 points

    Yes, please allow a couple of days for a better example to be provided.

    Regards, Andreas