4 Replies Latest reply on Mar 20, 2020 3:31 PM by AbFa_4663241

    Custom PCB Design for CYBT-423028-02

    AbFa_4663241

      Hi,

       

      To use a CYBT-423028-02 module on a custom PCB, what is the best practice to have capabilities for (1) programming the module on board using a standard USB-UART bridge (using a connector) and (2) communications including HCI commends with a host MCU?

       

      I understand that the only way to program the module (with CYW20719) is to use HCI UART interface (explained in KBA223458). The question is: if the HCI UART interface is exclusively used for programming, how the MCU can send HCI commends to CYW20719 after programming the module? Can PUART be used after the programming to send HCI commends in application mode or the HCI UART should be used?

      The Introduction of "WICED HCI UART Control Protocol (Doc. No.: 002-16618 Re)" page 9 explains that:

       

      "In the Bluetooth HCI mode, the MCU communicates to the CYW207xx device using the standard Bluetooth HCI protocol. In the Application mode, the MCU uses the WICED HCI protocol defined in this document."

       

      We are just confused how the connections should be designed on the pcb so both normal operation with a host MCU and programming using an external USB-UART bridge (see KBA223458 for example) are possible.

       

      Thanks!

        • 1. Re: Custom PCB Design for CYBT-423028-02
          AnjanaM_61

          Hi AbFa_4663241 ,

           

          Can you please let us know your application requirement ? Do you want to use the module in application mode or HCI mode? For both options you have to use HCI UART only.

           

          The chip can be in HCI mode or in application mode.  In the HCI mode, there is no embedded applications and device works as a Bluetooth HCI controller.  In the HCI mode the chip can process standard HCI commands/data from the host and will reply with HCI events/data. HCI communication is standard for all chips from all manufacturers and defined in the Bluetooth Core specification.

          Cypress chips also support embedded mode. Meaning that the host can load an embedded application which will run on the chip.  After embedded application is loaded, it can talk to the host, but not using HCI commands/events.  Typically a host talks to the embedded app using WICED HCI commands/events. These WICED HCI commands are explained in  WICED HCI UART Control Protocol document. ( for example refer implementation of  hci_audio_gateway demo example in WICED SDK ) 

           

          Please let us know in this which is your application requirement

           

          Regards,

          Anjana

          1 of 1 people found this helpful
          • 2. Re: Custom PCB Design for CYBT-423028-02
            AbFa_4663241

            Hi Anjana,

             

            Thank you for your quick response.

            Our application is to send bulk data from measurements performed on the host board to a PC, tablet or IOS device via a Bluetooth BR/EDR or BLE connection (SPP profile).

            The data is routinely collected by a separate MCU and then the CYBT-423028-02 module which is connected to the MCU will transmit to the PC. The MCU on-board should be also able to receive several data acquisition parameters from the PC side via the Bluetooth connection.

            I'm new in Bluetooth development but from your reply my understanding is that we should use the HCI mode. The question is: If we connect the HCI UART (the four pins) to our MCU UART interface, then how can we program the module? Will we need to program the module for this application at all even for our prototyping?

             

            Thank you for any help!

             

            Abi

            • 3. Re: Custom PCB Design for CYBT-423028-02
              AnjanaM_61

              Hi AbFa_4663241 ,

               

              Q) If we connect the HCI UART (the four pins) to our MCU UART interface, then how can we program the module? Will we need to program the module for this application at all even for our prototyping?

              A) If you are using HCI mode, ideally you don't have to program any application. However its recommended to program the chip with an empty application as mentioned here : CYW20719 in HCI mode

              You can either program it one time with any of our GUI tools ( WICED SDK / WICED Module Programmer User Guide – KBA225060  ) to all the modules prior connecting to the MCU. Or after connecting to the MCU you can use HCI commands to program as mentioned in WICED-HCI-Control-Protocol.pdf doc available in WICED SDK ( /20719-B1_Bluetooth/doc/WICED-HCI-Control-Protocol.pdf)

               

              Thanks,
              Anjana

              1 of 1 people found this helpful
              • 4. Re: Custom PCB Design for CYBT-423028-02
                AbFa_4663241

                Anjana,

                 

                Thank you so much for your response, your response was very helpful.

                 

                Abi