• Hi @all

    I tried to access external hardware over the SPI bus.
    Using /dev/spidev0.0

    Running a lightly modified spi_test.c let some strange timing diagram appear on the logic analizer.

    8 bits/word sending 3 bytes give not 3*8*2 baud: I expected the clock would be:
    CS0 10000000000000000000000001
    byte: 111111112222222233333333
    clock 010101010101010101010101

    The LA shows:
    CS0 1000000000000000000001111
    byte: 111111122222223333333xxx
    clock 101010110101011010101xxx

    I use gpio 41 as CS0 which is assigned in the structure spi_ioc_transfer.pad

    Trying to change clock phase or polarity cause an error message.
    Change the bits/word works but it unusable, we need 8/word

    The timing between lowering CS0 and rising clock is very small - few ns
    The clock low phase between two bytes is very small - fw ns

    The connected chip (CMX865A) is not responding.

    any suggestions?

    beste regards