3 Replies Latest reply on Jul 17, 2020 6:15 AM by MallikaK_41

    The LVTTL setting for CCG3PA(CYPD3171)

    NoAr_1540581

      Hello

       

      We are thinking of connecting SOC and CCG3PA with I2C.

      However, I/O Voltage is different as shown below.

      - SOC I/O voltage is 3.3V

      -CCG3PA I/O voltage is 5V

       

      However, I want to make I2C communication by setting the CCG3PA as LVTTL instead of CMOS, but I do not know how to set it to LVTTL, so please tell me the method.

       

       

      Best Regards

      Arai

        • 1. Re: The LVTTL setting for CCG3PA(CYPD3171)
          MallikaK_41

          Hi Arai,

           

          >>Is there any specific reason of operating CCG3PA at 5V?

          You can power CCG3PA using VDDD=3.3 V if there are no power constraints in your system, i/o will also be equal to VDDD=3.3 V.

          This way the CCG3PA will be compatible with the SOC.

           

          >>Can you tell the mode in which SOC is operating (CMOS or LVTTL)?

           

          Best Regards,

          Mallika

          • 2. Re: The LVTTL setting for CCG3PA(CYPD3171)
            NoAr_1540581

            Hello Mallika san

             

            I have to control external parts with 5V, so I will use CCG3PA GPIO as 5V.
            Therefore, when connecting to SOC (3.3V), it is necessary to use the terminal as LVTTL, so we have confirmed how to make it function as LVTTL.

            Please tell me what kind of method there is such as changing the port type of P3.3 on PSoC Creator, and other method. In addition please tell me If there are restrictions on settings LVTTL.

             

            Best Regards

            Arai

            • 3. Re: The LVTTL setting for CCG3PA(CYPD3171)
              MallikaK_41

              Hello Arai-san,

               

              You can change the input threshold of a gpio using PSoC Creator to LVTTL.

              screenshot.png

              However, on changing the threshold to LVTTL, only the input buffer of the gpio will change, that means basically the VIH, VIL, VOL, VOH thresholds will change but the device VDD will remain the same, i.e at 5V.

              So reading the input won't be a problem.

              However since the CCG3PA VCC will remain at 5V, it won't be compatible with the 3.3 V SOC and thus output will be a problem for you.

               

              Best Regards,

              Mallika