3 Replies Latest reply on May 20, 2015 11:36 AM by user_14586677

    Floating I2C pins?

    user_35676618

       Hi, I'm finishing up a prototype design using the PSoC4013.  I'm using the I2C pins for factory calibration with the MiniProg3 as an I2C bridge.  I read that the miniprog3 has the pullups, so they're not needed for communication.  I know its probably not advised, but will floating I2C pins cause any problems after leaving the factory, ie increased current draw, phantom communication etc?  Will executing a EZI2C_Stop() be enough to alleviate the problem?

         

      Thanks,

         

      Ken

        • 1. Re: Floating I2C pins?
          user_14586677

          I looked at the EZ code for stop, its not clear to me whether GPIO

             

          is in fact put in a known state, and whgat state.

             

           

             

          You could do your own GPIO register writes to force the pin state,

             

          this ap note discusses how -

             

           

             

              

             

                   

             

          http://www.cypress.com/?rID=93401     AN86439 - PSoC® 4 - Using GPIO Pins

             

           

             

           

             

          and restore the state prior to issue Ez_Start( ).

             

           

             

          However I still advise you file a CASE and ask if the above is necessary, if so what

             

          is the correct way to do this.

             

           

             

          One other possibility, add pullups on the board.

             

           

             

          Regards, Dana.

             

           

             

              

             

                   

             

          To create a technical case at Cypress -

             

           

             

          www.cypress.com

             

          “Support”

             

          “Technical Support”

             

          “Create a Case”

             

           

             

          You have to be registered on Cypress web site first.

          • 2. Re: Floating I2C pins?
            user_35676618

             Hi Dana, Thanks for looking into this for me.  I thought about relaying out the PCB, but its a small board packed with parts already.  I thought the best option might be to disable the I2C pins after factory cal.  I'll submit a case and see what they say.

               

             

               

            Thanks!

               

            Ken

            • 3. Re: Floating I2C pins?
              user_14586677

              Glad to have been of assistance.

                 

               

                 

              Regards, Dana.