1 Reply Latest reply on Sep 10, 2015 1:31 PM by user_242978793

    Question about VDDD, USB, and Programming

    rick.pease

      Hello,

         

       

         

      I'm working on a layout that is using a PSOC5LP. I'd like to run the PSOC5LP off 3.3V but still provide a USB interface with computers. With VDDD hooked to 3.3V, I'll have to set the USBUART block to run in 3.3 mode, is there anything I have to hook up externally to the USB pins to make it work with a computer? If VDDD is set to 3.3V and I use a 5V computer USB input, am I destined to destroy the PSOC?

         

       

         

       

         

      Thanks for the help in advanced,

        • 1. Re: Question about VDDD, USB, and Programming
          user_242978793

          Ro4: You have to remove diode D1 from the board if you plan to run the board on 3.3 Volts and you have to remove the On Board  Programming section of the 5LP. And program it with that before you connect your external Power source. 

             


          Note:
          In order to use an external power supply, while KitProg is connected to the PCB USB, remove
          diode, D1, from the board. This ensures that VTARG supply from KitProg is not supplied to the target
          device. KitProg measures the target voltage and adjusts the logic levels on the programming pins
          accordingly.
          It is important to understand that this prototyping kit does not have any onboard ESD protection
          circuitry. Therefore, the power source for the PSoC 5LP Prototyping Kit must be of a high quality to
          ensure that the board is protected from any over-current conditions and swapped-power
          connections.