2 Replies Latest reply on Dec 11, 2018 6:40 AM by naroc_3877611

    How to program CYBT_423028_02 using external HCI UART interface


      I'm new to Cypress MCUs and did a quick search through the forum, but wasn't able to find an answer for this specific question.


      I'm developing an application targeting the CYBT_423028_02 module, currently running on the CYBT_423028_EVAL target board. If I leave SW4 switch positions on so that HCI UART interface is connected to the onboard USB to serial bridge, I can download an application to the MCU just fine using WICED Studio, which is great.


      The problem is that I can't get the external interface working so I can prove we can program these modules once we've soldered them to real PCBs. I'm currently trying to use an FTDI 3.3V USB to UART serial bridge cable to connect the external HCI UART interface (J1) to the PC, but WICED Studio fails to recognize the module if I do that (even if I specify specifically which UART COM port to use). The eval board documentation only specifies the programming procedure if you're using the onboard interface, and the datasheet for the module doesn't specify the programming procedure at all aside from mentioning that the HCI UART interface exists, as I suppose one should expect from a device datasheet.


      After some searching through getting started guides that are linked to the module on the website, in the Getting Started with EZ-BLE WICED Modules guide (Document No. 002-20929), I notice on page 64 the following bullet point text. The connector information is for another board, but it is a getting started guide linked to the CYBT_423028_02 product page, so I'm assuming the general information applies to the whole family of devices:


      "HCI UART direct connection header (J2): The J2 header provides all HCI UART communication lines to the user. This allows for connection to the EZ-BLE WICED Module without having to connect through USB. This can be used to connect a host controller evaluation board directly to the EZ-BLE WICED Module HCI UART connection. HCI UART connections are not brought out to the Arduino-compatible headers.".


      This would imply that there's a special bridge board you need to accomplish what I'm trying to do (host controller evaluation board), but there's zero references to what this hardware is and where I can obtain it from.


      So what is the correct procedure using WICED Studio and external hardware that can be used for programming standalone CYBT_423028_02 modules on custom PCBs? Is there special programming hardware involved, and what specifically is that hardware if so? Thanks in advance.