1 Reply Latest reply on Mar 23, 2020 8:55 PM by JayakrishnaT_76

    CYUSB3KIT-003 uart and Jtag




      I'm using cyfxusbi2sdmamode.c example. It configures uart and i2s.

      Where this uart is located ?

      - Some virtual uart through USB3 cable into my Host ?

      - Or it the one exposed by micro usb jtag cable ?


      The code says:

          /* Configure the IO matrix for the device. On the FX3 DVK board, the COM port

           * is connected to the IO(53:56). So since we need to use both I2S and UART,

           * configure the GPIF bus to be 32 bit. This does not mean that the GPIF has

           * to be in 32 bit configuration, it just means that the whole 32bit shall be

           * reserved for the GPIF interface and not available for GPIO. Another option

           * is to not use UART, and use I2S_ONLY mode or use an external UART controller

           * on the IO(46:49). */


      Where is this IO(53:56) ? Can you explain what is IO(53:56) ?

      Looking at "SuperSpeed Explorer Kit Schematic.pdf" I can't find IO(53:56).

        • 1. Re: CYUSB3KIT-003 uart and Jtag



          UART is used for sending the debug information to the host through a USB 2.0 cable. This is done by making use of a USB-Serial Converter chip as shown in page 8 of the SuperSpeed Explorer Kit Schematic.

          IO(53:56) refers to GPIO 53:56 of the FX3 chip. Please find the pin description for FX3 chip at page 15 of the FX3 Datasheet. The link to the same is given below:


          From this, you can understand that when the GPIF bus width is configured to be 32 bits (as done by this example project), GPIO 53:56 can be used as COM port. If the GPIF data bus width is configured to be 16 bits, then depending on the io_cfg.lppMode, GPIO 53:56 can be used as UART/SPI.


          Best Regards,