1 Reply Latest reply on Apr 16, 2014 4:35 PM by user_14586677

    Series Resistor between PSoC and Bluetooth Module

    john.ramshur

      My current design uses a PSoC3 and Microchip RN42 Bluetooth module. I haven't been using a series resistor on the UART lines between the two devices, but I see a lot of design that do use series resistors between digital communication lines. 

         

       

         

      Should I include series resistors between PSoC and BT module? Looks like the RN42 can handle a max of 5mA per pin.

        • 1. Re: Series Resistor between PSoC and Bluetooth Module
          user_14586677

          Series R's are used primarilily in high speed digital routes

             

          to kill the over/undershoot generated by L in route, basically

             

          make L look incredibly lossy. If using your scope you see under

             

          and overshoot that exceeds specs then consider them.

             

           

             

          Usually they are picked for a specific layout, trial an error, but

             

          20 - 100 ohms typical values.

             

           

             

          Regards, Dana.