6 Replies Latest reply on Jan 13, 2020 9:44 PM by ChHs_4614611

    External powerr issue

    ChHs_4614611

      Hello Guys,

       

      Now I have a problem about external power.

      When the board power on 5.0V is not working.

      If I adjust power to 3.3V is working no problem.

       

      I also change the PSoC Creator's setting to 5.0.

      But, result is same not working in 5V.

      Am I missing something ?

       

      [PSoc Creator setting]

      ExternalPower.jpg

      [My board's schematic]

       

      CY8C4125.jpg

        • 1. Re: External powerr issue
          EktaN_26

          Hello Cheng,

           

          A. Please follow the following guidelines for schematic:

          1) In case of Unregulated External Power Supply the VDDA an VDDD pins should be connected to power supply via 1uF and 0.1uF parallel capacitors as shown in the figure below.

          2) XRES pin is active LOW. XRES is internally pulled up to VDDD via a 5.6-kΩ resistor; you do not need an external pull-up resistor for XRES.

           

          Refer to the PSoC 4 Hardware Consideration Guide for more details on this: https://www.cypress.com/file/141176/download

           

          B. Also, can you let me know what do you mean by "When the board power on 5.0V is not working." Does this mean that you are able to program successfully but are facing issues with the working part.

           

          C. Measure the voltage on the VCCD pin, it should be 1.8V, since the output of the regulators routed to this pin.

           

          Best Regards

          Ekta

          • 2. Re: External powerr issue
            ChHs_4614611

            Hi Ekta,

             

            B. Also, can you let me know what do you mean by "When the board power on 5.0V is not working." Does this mean that you are able to program successfully but are facing issues with the working part.

             

            I use a sample code for test (LED toggle per 500ms)

            When VDD is 3.3V. MCU is running.

            If VDD change to  5.0V. MCU looks like no running. Because LED is no toggle.

            • 3. Re: External powerr issue
              EktaN_26

              Hi Cheng,

               

              1) Can you please attach the complete schematic as well as the project that you are using for testing , this would help us to check the connection of the LED and other issues that might be present.

               

              2) In PSoC Creator when testing for the 5V case, please perform the following steps:

              • Connect the device to your PC
              • In PSoC Creator goto Debug tab and select Attach to running Target.
              • In the Attach to Target dialogue box, select the device. (ensure halt target on attach check box is selected)
              • Click OK

              Let us know about the point a which the program halted.

               

              3) As mentioned in the previous response, Measure the voltage at the VCCD pin. If the voltage is 1.8V, then there is no issue with the chip.

               

              Best Regards

              Ekta

              • 4. Re: External powerr issue
                ChHs_4614611

                Dear Ekta,

                 

                1) The complete schematic PDF file I put to google drive .

                https://drive.google.com/open?id=13ogM0BK4G4OZ4veXJlVTs7H0iFMK9hu0

                I replace  R147 to LED for test.

                 

                2) I find the program is running in debug.  But, I/O output no change in 5V.

                error01.jpg

                error02.jpg

                 

                3) I have confirmed that VCCD is 1.8V.

                • 5. Re: External powerr issue
                  XiaoweiZ_71

                  Seems no error in schematic.

                  Could you replace R147 back to resistor or resistor+led then repeat the test?  Without a current limit resistor, sink current on P4.3 may excess absolute maximum spec of per GPIO (25mA),  i am not sure if this may cause abnormal IO logic.

                   

                  In addition, please check C33, confirm the cap value is 1uF or 100nF. 

                  2 of 2 people found this helpful
                  • 6. Re: External powerr issue
                    ChHs_4614611

                    HI,

                     

                    I try resistor+led .Now I/O is working well.

                    I think the problem is the same as what you said should be caused by excessive current.

                     

                    Thank you very much for your help~