SPI timing

      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