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Does Pi need the reset line?

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  • Does Pi need the reset line?

    Hi guys,

    I have used the 43PCT extensively on the Arduino platform, wiring it direct to the Arduino without the adapter shield. I have always used a reset line to sync the arduino when booting (as recommended).

    I am now looking at migrating from Arduino to Raspberry Pi and have read the App Note to again hook it up directly without a shield/hat.

    In the app note I notice there is no use of the reset line .. is this required with the R Pi?

    Thanks for your help.


  • #2
    Hi Kurtle,

    The reset line is not badly needed when connecting the 4D Systems display to the Raspberry Pi. Since the two devices could establish communication as long as both halves of the serial/UART communication are configured properly.

    ** The reset line could be manually wired to any of the Raspberry Pi GPIO and is dependent on the user's application needs.



    • #3
      Hi Kurtle

      To extend what Bryan said, yes its not required, but it can be useful.

      It is not required for the Arduino either, however that is based on the Arduino not sending anything before the display is powered up and ready, this is the main ready for the reset.
      With the pi, typically you power the pi up and the display too, and then when the Pi is loaded, you run the program and it talks to the display, so there is plenty of time for the display to start up.
      That said however, depending on your Pi setup, you might send 'rubbish' on the Serial Port when you boot - which isnt something we have control of. So in some cases, yes, you will need the reset to put the display in a known state, as this 'rubbish' could upset the comms. Its best to get the Pi to be silent on the Serial Port when it starts, however I am personally unsure if this is possible or what.

      We hope to design a new Pi adaptor in the next little while, which will include a reset pin. So its there at least if required.
      For now, if you need one, you could just solder a wire on to the RES header base, and then plug the other end of it into your Pi somewhere suitable.



      • #4
        Thank you Bryan and James for the replies.