2 Replies Latest reply on Jun 25, 2020 10:19 PM by anng_4696981

    setup output open drain pin

    anng_4696981

      I setup the output pin to open drain mode, but it only drives the pin so other chips cannot drive it.

        • 1. Re: setup output open drain pin
          MoTa_728816

          Hi,

           

          > I setup the output pin to open drain mode, but it only drives the pin so other chips cannot drive it.

           

          There are 2 kinds of open drain modes.

          Which one are you using?

           

          (1) OpenDrain drives high

          001-open_drain_drive_high.JPG

           

          (2) OpenDrain drives low

          002-open_drain_drive_log.JPG

           

          Also what do you mean with "drive"?

          Do you mean PSoC drives the pin to both High and Low, or only to High or only to Low?

          > but it only drives the pin so other chips cannot drive it.

           

          As far as I have been using PSoC with I2C devices, they are working.

          Which means at least OpenDrain drives to Low with external pull-up resistors and other I2C devices are working.

           

          So would you let us know the configuration of the pin and what kind of circuit(s) are connected externally?

           

          It would be nice, if you can attache a simple sample project which can reproduce the problem.

          To attach a project, please refer to the following discussion.

          How to attach a project archive file to a question?

           

          moto

          • 2. Re: setup output open drain pin
            anng_4696981

            Hi Motoo,

            I need an open drained output with an external PU.  Any chip on the bus can pull it low or release it.

            I set it to Open Drain Drive high, so no other chip can drive it low.

            I found that after I changed it to Open Drain Low, it works now.

            Yes, it works like an I2c pin.

             

            Thanks for your support.

             

            Best Regards,

             

            Anh Ngo