6 Replies Latest reply on Mar 6, 2020 2:11 AM by XinghaoZ_26

    CYBT-353027-EVAL PUART FLOW CONTROL

    EdUg_4645656

      I downloaded EZ-Serial on the CYBT-353027-02 module of the CYBT-353027-EVAL Evaluation Board in order to build a Bluetooth/UART bridge with flow control enabled.

      The EZ-Serial user manual highlights the following code (sent via USB/UART bridge) as the way to set up some parameters, such as baudrate, parity and flow control

       

      STU,B=1C200,A=0,C=0,F=1,D=8,P=0,S=1

       

      after sending this line using PuTTY the supposedly "success response" (as indicated by the manual) is given and appears as follows

       

      @R,0009,STU,0000

       

      Now the flow control is supposed to be enabled and the correspondent signal should be on GPIO_4 of the Evaluation Board but when I send data in both ways (UART->Bluetooth and Bluetooth->UART) the signal on GPIO_4 doesn't move at all (checked with an oscilloscope).

       

      Am I doing anything wrong? Is there any way to make flow control work on PUART?

       

      Thanks in advance

        • 1. Re: CYBT-353027-EVAL PUART FLOW CONTROL
          XinghaoZ_26

          The STU is a protected configuration setting. You need to send the "STU$,B=1C200,A=0,C=0,F=1,D=8,P=0,S=1" again to make it work. It is documented in the user guide as follows:

          • 2. Re: CYBT-353027-EVAL PUART FLOW CONTROL
            EdUg_4645656

            I tried but unfortunately nothing changed, the GPIO_4 signal is still steady while sending data both ways.

            Is there any other operation to be executed in order to enable flow control on PUART? Are there any other parameters to be set?

             

            Thanks

            • 3. Re: CYBT-353027-EVAL PUART FLOW CONTROL
              XinghaoZ_26

              I just check with EZ-Serial FW engineer. The RTS is not avaliable in the current EZ-Serial. We are working on this problem.

              It will be fixed in the later FW.

              1 of 1 people found this helpful
              • 4. Re: CYBT-353027-EVAL PUART FLOW CONTROL
                XinghaoZ_26

                Sorry for my mistake. The RTS for the CYBT-353027  is already supported in the current EZ-Serial FW.

                RTS is low in default. When WICED module can not receive data, it pull RTS to high to prevent peer send more data. You must send data fast enough. We suggest you test with Tera Term UART tool because it can send data quite fast.

                • 5. Re: CYBT-353027-EVAL PUART FLOW CONTROL
                  EdUg_4645656

                  I just tried Tera Term but I cannot see any logic state variation, on the oscilloscope, related to GPIO_4 signal while transmitting.

                  I've attached a couple of pictures (oscilloscope screenshot and CYBT-353027-EVAL wiring up) to avoid misunderstandings.image1.jpegimage0.jpeg

                  • 6. Re: CYBT-353027-EVAL PUART FLOW CONTROL
                    XinghaoZ_26

                    353027 EVAL board does not connect RTS pin(P1/GPIO4) of module to  usb2uart chip. So you have to use external USB2UART converter.

                    1. Put pin of PUART(SW5) of 353027 EVAL  to off.
                    2. Connect VDD, Gnd, PUART_RXD(J7),PUART_TXD(J7),RTS(GPIO_4 in J4),CTS(I2C_SDA/P3 in J4) to relative pins of  USB2UART.

                     

                    Test Steps:

                    1. STU, F=1 . set flow control
                    2. Start  TeraTerm and connect to COM port of  above USB2UART which connect to 353027 EVA.

                            Using flow control as HARDWARE.

                       3. Start  SPP(or CYSPP) connection to 353027.

                       4. In Tera term terminal, send  file. If you only send few data or commands, it won't triger the RTS signal because the PUART can always receive more data.

                     

                    We can observe that GPIO_4 have high plus which is RTS signal.