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    Conn_SD Write Protect and Detect Switch Pins?

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    • bkolligsundefined
      bkolligs
      last edited by

      Hi all,
      Here's my problem:
      I'm making a PCB that includes an SD card reader (not microSD) that I plan to connect to the Conn_SD using a 10 pin ribbon wire. I have outlined the specific connection on the duet schematic in green for clarity.

      DuetSDConn.jpg

      Now the reader I plan to use has two additional switches on it: a write protect switch and a detect switch. This picture shows the reader component's PCB pattern. I outlined solder paste locations in gold, and the switches in question in red.

      SDReaderSwitches.jpg

      I'm wondering if the duet needs me to connect either of these switches to a specific pin from the Conn_SD pin array in order for the duet to read/write to the SD. Can I ignore the switches and just worry about tracing the 9 SD pins? Or do I connect VCC to the detect switch and just leave it high?

      Any assistance would be appreciated, thanks.

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      • dc42undefined
        dc42 administrators
        last edited by

        RRF doesn't need the card detect or write protect pins for external SD cards. It could support the card detect pin with a small firmware change.

        Duet WiFi hardware designer and firmware engineer
        Please do not ask me for Duet support via PM or email, use the forum
        http://www.escher3d.com, https://miscsolutions.wordpress.com

        bkolligsundefined 1 Reply Last reply Reply Quote 0
        • bkolligsundefined
          bkolligs @dc42
          last edited by

          @dc42 So in the event I'm using 5V for VCC, the extra pin on the Conn_SD board (since the SD card only needs nine pins) would be the 3.3V?

          dc42undefined 1 Reply Last reply Reply Quote 0
          • dc42undefined
            dc42 administrators @bkolligs
            last edited by

            @bkolligs said in Conn_SD Write Protect and Detect Switch Pins?:

            @dc42 So in the event I'm using 5V for VCC, the extra pin on the Conn_SD board (since the SD card only needs nine pins) would be the 3.3V?

            Do you mean that your SD card reader includes its own 5V to 3.3V regulator, and you are powering it from 5V? If so, check that your SD card reader doesn't have other electronics on it, such as level-shifters.

            Duet WiFi hardware designer and firmware engineer
            Please do not ask me for Duet support via PM or email, use the forum
            http://www.escher3d.com, https://miscsolutions.wordpress.com

            bkolligsundefined 1 Reply Last reply Reply Quote 0
            • jckrayundefined
              jckray
              last edited by

              @dc42 In the event that we did want to allow detect pin functionality what pin would we route that switch to? What firmware change would you need to make?
              I think it'd be nice if the system would prompt the user with a "SD card inserted" type message.

              John
              Founder of Hydra Research LLC, developers of the open-source 3D printers and providers of 3D printing services.
              https://www.hydraresearch3d.com/

              dc42undefined 1 Reply Last reply Reply Quote 0
              • bkolligsundefined
                bkolligs @dc42
                last edited by bkolligs

                @dc42 I will be powering the SD card with 3.3V, so I don't think I'd need to use the 5V pin. Also, I am assuming the duet uses SPI based off the pin names.

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                • dc42undefined
                  dc42 administrators @jckray
                  last edited by

                  @jckray said in Conn_SD Write Protect and Detect Switch Pins?:

                  @dc42 In the event that we did want to allow detect pin functionality what pin would we route that switch to? What firmware change would you need to make?
                  I think it'd be nice if the system would prompt the user with a "SD card inserted" type message.

                  You would have to pick a pin on the expansion board connector that you were not otherwise using. The card detect pins are listed in file Pins_DuetNG.h.

                  Duet WiFi hardware designer and firmware engineer
                  Please do not ask me for Duet support via PM or email, use the forum
                  http://www.escher3d.com, https://miscsolutions.wordpress.com

                  bkolligsundefined 2 Replies Last reply Reply Quote 0
                  • bkolligsundefined
                    bkolligs @dc42
                    last edited by

                    @dc42 So if we did want to do that then we could write our own firmware change to allow the detect functionality?

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                    • bkolligsundefined
                      bkolligs @dc42
                      last edited by

                      @dc42 Where is that header file located in the git repo? I would like to take a look.

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