4 Replies Latest reply on Jul 17, 2014 4:23 PM by MichaelF_56

    BCM920736 SIP HCI UART Debugging

      It appears that in the 2.x environment that this is the default setup:


      However, I'm not seeing any movement on the TX and RX lines on my scope.  I am able to program and run the sample apps on my board and am basing my code on the mybeacon sample app.


      What do I need to do to enable debug out?

        • 1. Re: BCM920736 SIP HCI UART Debugging

          Take a look at the SDK 2.0 Quick Start Guide here: The specified item was not found.


          Go to the section titled "Viewing Traces From WICED SMART Tag"


          This should contain everything you need.

          • 2. Re: BCM920736 SIP HCI UART Debugging

            I am not using TAG board, I am using a SIP module on a custom board.


            I can program AND run my app but I never see any movement on the uart lines in application mode.  Is there anything else that would cause the UART not to work on the firmware side?  The only hardware difference is that the quick start guide wants me to disconnect the RX line completely. (SW2.2 = OFF), which I can't do easily.  This shouldn't matter as it's pulled down internally on boot.

            • 3. Re: BCM920736 SIP HCI UART Debugging

              The correct answer is no, nothing else is required. 


              I started seeing movement on my scope as soon as I posted my last message.  No clue why.


              For some reason the eclipse terminal still isn't working but I was able to connect teraterm and see debug output for the first time.  Woo Hoo!  I suspect the baud rate is/was incorrect and wasn't resetting properly to 115200 until I restarted everything.

              • 4. Re: BCM920736 SIP HCI UART Debugging

                If you were using SDK 2.0.1 and a BCM92073X_LE_KIT Tag board, then the traces being output are encoded.


                There is an Eclipse plugin that's installed within the Windows version of the IDE which will allow you to view the encoded traces.


                More on this topic here: Re: Scrambled output via serial port


                The baud rate seems to only work correclty when set to 115200. That may have been the issue.


                Another thing you will want to check is the state of the HCI UART Rx line during reset as this determines the mode.


                By default, there is a 10k pull down on Rx that's internal to the module which should keep the line from going into programming mode.  However, if you are using something like an FTDI USB to Serial converter between your PC and the board, it's possible that the FTDI device could be pulling the Rx line of the HCI UART high and preventing the device from going into application mode.


                When sampled on RESET only:

                HCI UART Rx = High (Programming mode)

                HCI UART Rx = Low (Application mode)