11 Replies Latest reply on Jan 29, 2016 12:43 AM by Leon

    I210 unused pins connection

    Arnauld Community Member

      Hi,

      We are in the process of designing a new embedded system around the i210 and I have a question with regards to connecting various unused pins.

      Please note that we do not need the JTAG interface nor the NC-SI. Intel recommends using pull-up and/or pull-down resistors for those (unconnected) pins. (See Pull-Up/Pull-Down Resistors: Page 22, DS 2.7)

      This obviously eats up board space and complicates the layout.

      Basically my question is, can we direct connect the unused input pins for JTAG and NC-SI to either 3.3V or ground?

      And also what about the NC-SI output pins, do they still need PU (NC_SI_RXD[1:0]) and PD (NC_SI_CRS_DV) if the interface is not connected/used?

      Thank you.

      Best regards,

      Arnauld

        • Re: I210 unused pins connection
          gabriel.thomas Brown Belt

          Hello Arnauld.

           

          Welcome to Intel® Embedded Community.

          We are checking your thread and will post an update as soon as possible.

           

          Regards.

           

          Gabriel Thomas.

          • Re: I210 unused pins connection
            jc Brown Belt

            Hi Arnauld Guiheneuf

             

            Please follow recommendations from table 2-1 Pull-Up Resistors for design, these have been validated by Intel®.

             

            Note that even JTAG_CLK should be pulled up even when no clock device is connected to it.

             

            Regards.

            Josue.

              • Re: I210 unused pins connection
                Arnauld Community Member

                Hi Josue,

                 

                I understand that Intel has made recommendations on pull-up/down resistors and in effect validated their use for an i210 design

                I also fully appreciate that unused input pins need pull-up/down and I do not intend to leave them floating.

                 

                I will follow Intel's recommendation on PU/PD detailed in Table 2-1 pins but my question was a bit more specific:

                Do you see any issue in connecting recommended PU/PD INPUT pins directly with a trace to 3.3V/GND respectively? (Again, I do not plan to use JTAG or NC-SI)

                 

                Now with regards to the NC-SI OUTPUT pins, do they still need PU (NC_SI_RXD[1:0]) and PD (NC_SI_CRS_DV) if the interface is not connected?

                I could not see any strapping function on those output pins therefore I do not see why they would need pull-up/down resistors when not used. Please advise.

                 

                Best regards,

                Arnauld