1 Reply Latest reply on Sep 12, 2019 5:07 AM by RakshithM_16

    SPI Slave Select Multiple pins

    RoRo_3281831

      I am having some trouble with the SPI SCB.

       

      I have a chip which my PSoC4 is using SPI to talk to.  I am in the middle of developing the SPI interface code, so I'm using a scope to instrument the SPI signals to aid in my development.  The SCLK, MISO, and MOSI lines are all available on an inter-board connector, so I can connect to those easily.

       

      However, the SS line is buried on the board, and rather than trying to attach a tiny wire, I figured I could just duplicate the SS signal out of an available GPIO pin that runs out to my connector.  However, when I do that, the signal doesn't seem to get duplicated.  The SS line is toggling, but the duplicate remains high, or vice versa.

       

      My PSoC schematic has the SPI module display the pins, and I've wired up the SCLK, MISO, and MOSI lines.  I have the SS line running to both the "real" SS line for the chip and another digital output pin wired in parallel with it.  But only one of them ever toggles.

       

      Why is that?  How can I fix that?