7 Replies Latest reply on Dec 30, 2015 3:07 PM by user_78878863

    psoc 5lp GPIO  high impedance digital input  can not work

    xiantong_ma_1540881

      Hello
          i use psoc 5 CY8C5888 ( CY8CKIT-059 PSoC® 5LP Prototyping Kit)in my design. the design used to monitor digital signal.

         

          so i want to configure gpio pin as high impedance digital input ,
          But when i measure the value of the resistor on pin after programming the kit. there is 2.4k resistor pull-up to 5V.

         


      Thanks

        • 1. Re: psoc 5lp GPIO  high impedance digital input  can not work
          xiantong_ma_1540881

          the report from the compiler

             

              Pin : Name = mysignal1(0)

             

                  Attributes:

             

                      In Group/Port: True

             

                      In Sync Option: SYNC

             

                      Out Sync Option: AUTO

             

                      Interrupt generated: False

             

                      Interrupt mode: NONE

             

                      Drive mode: HI_Z_DIGITAL

             

                      VTrip: CMOS

             

                      Slew: FAST

             

                      Input Sync needed: True

             

                      Output Sync needed: False

             

                      SC shield enabled: False

             

                      POR State: ANY

             

                      LCD Mode: COMMON

             

                      Register Mode: RegComb

             

                      CaSense Mode: NEITHER

             

                      Treat as pin: True

             

                      Is OE Registered: False

             

                      Uses Analog: False

             

                      Can contain Digital: True

             

                      Is SIO: True

             

                      SIO Output Buf: NONREGULATED

             

                      SIO Input Buf: DIFFERENTIAL

             

                      SIO HiFreq: LOW

             

                      SIO Hyst: ENABLED

             

                      SIO Vtrip: MULTIPLIER_0_4_OR_1

             

                      SIO RefSel: VCC_IO

             

                      Required Capabilitites: DIGITAL, ROUTABLE, SIO

             

                      Initial Value: 1

             

                      IO Voltage: 0

             

                  PORT MAP (

             

                      pa_out => mysignal1(0)__PA ,

             

                      fb => Net_2 ,

             

                      pad => mysignal1(0)_PAD );

             

                  Properties:

             

                  {

             

                  }

             

           

             

              Pin : Name = mysignal2(0)

             

                  Attributes:

             

                      In Group/Port: True

             

                      In Sync Option: SYNC

             

                      Out Sync Option: AUTO

             

                      Interrupt generated: False

             

                      Interrupt mode: NONE

             

                      Drive mode: HI_Z_DIGITAL

             

                      VTrip: CMOS

             

                      Slew: FAST

             

                      Input Sync needed: True

             

                      Output Sync needed: False

             

                      SC shield enabled: False

             

                      POR State: ANY

             

                      LCD Mode: COMMON

             

                      Register Mode: RegComb

             

                      CaSense Mode: NEITHER

             

                      Treat as pin: True

             

                      Is OE Registered: False

             

                      Uses Analog: False

             

                      Can contain Digital: True

             

                      Is SIO: True

             

                      SIO Output Buf: NONREGULATED

             

                      SIO Input Buf: DIFFERENTIAL

             

                      SIO HiFreq: LOW

             

                      SIO Hyst: ENABLED

             

                      SIO Vtrip: MULTIPLIER_0_4_OR_1

             

                      SIO RefSel: VCC_IO

             

                      Required Capabilitites: DIGITAL, ROUTABLE, SIO

             

                      Initial Value: 1

             

                      IO Voltage: 0

             

                  PORT MAP (

             

                      pa_out => mysignal2(0)__PA ,

             

                      fb => Net_1 ,

             

                      pad => mysignal2(0)_PAD );

             

                  Properties:

             

                  {

             

                  }

             

              </CYPRESSTAG>

             

              <CYPRESSTAG name="Macrocell listing" icon="FILE_RPT_EQUATION">

          • 2. Re: psoc 5lp GPIO  high impedance digital input  can not work
            user_1377889

            Welcome in the forum!

               

            Can you post your complete project, so that we all can have a look at all of your settings? To do so, use
            Creator->File->Create Workspace Bundle (minimal)
            and attach the resulting file.

               

             

               

            Bob

            • 3. Re: psoc 5lp GPIO  high impedance digital input  can not work
              user_78878863

              How do you measure the input resistance? Just with a DMM? Are you sure, then, that you are not applying a reverse voltage to the pin?

                 

              Best way to measure is to use a DMM in current measurement mode to measure the actual current flowing in or out of the pin (just connect the DMM between the pin and GND / Vcc).

              • 4. Re: psoc 5lp GPIO  high impedance digital input  can not work
                xiantong_ma_1540881

                thank you for your reply.
                i have measure the voltage and current.
                i use 12.0(scl)pin as input pin
                voltage:
                12.0(scl)pin to GND: 4.84v
                12.0(scl)pin to VDD: 0v
                 
                current:
                12.0(scl)pin to GND: 1.25mA
                12.0(scl)pin to VDD: -0.04mA

                   

                so the internal pull up resistor is: 3.872k to 5v

                • 5. Re: psoc 5lp GPIO  high impedance digital input  can not work
                  xiantong_ma_1540881

                  Hi, Bob

                     

                      my psoc 5lp project is in attachments.

                  • 6. Re: psoc 5lp GPIO  high impedance digital input  can not work
                    user_1377889

                    Indeed have the port12 Pins 0 and 1 resistors on the board as shown in the -059 schematic, because these are the pins for I2C programming of the target chip.

                       

                     

                       

                    Bob

                    • 7. Re: psoc 5lp GPIO  high impedance digital input  can not work
                      user_78878863

                      When in doubt, look at the schematic :)