3 Replies Latest reply on Jun 17, 2020 12:25 AM by DheerajP_41

    Sniff Mode Blocks SPP Transmissions




      I am using a CYBT-413034 module to implement the BT SPP profile in Wiced Studio 6.2.0


      I've got the SPP example running on the board, and can pair and connect with the device.

      When the spp connection is up, I begin streaming data periodically out. I notice after several minutes of operation that the transmissions halt. I've tried increasing the no. of  buffers used by the SPP (wiced_bt_cfg_buf_pools) but this has not helped.


      I have noticed that I receive a change in power status notification Power mgmt status event: bd (b8 31 b5 82 be c7 ) status:2 hci_status:0 coincidental with the transmission failure. I attempt to set the module back to normal by issuing a wiced_bt_dev_cancel_sniff_mode() request, but by that point its too late, my streaming service has halted.


      I have seen the previous post on SNIFF, but I'm not convinced this mode does not affect the ability to transmit.

      Is there any way to disable the SNIFF mode and run in a normal power state with this module?



      Keith Fowler

        • 1. Re: Sniff Mode Blocks SPP Transmissions



          Could you please provide us the testing log (with timestamp) and steps to reproduce this issue ?

          What are the modification you have done in your application?


          If transmission fails, power status change can occur. Nothing wrong in it.




          • 2. Re: Sniff Mode Blocks SPP Transmissions

            I had originally thought the module change to sniff power mode was the cause of the transmission halt. Now I believe the mode change is a symptom of failed transmissions, as you mentioned. Are there Bluetooth statistics or diagnostics available on the module to help determine the cause of dropped communications and the sniff mode event?




            • 3. Re: Sniff Mode Blocks SPP Transmissions



              There are few flags defined in the SPP application itself which will be helpful for testing.

              Also, you can try printing the buffer statistics (wiced_bt_get_buffer_usage) periodically to monitor it.


              Following compilation flags are important for testing:

              HCI_TRACE_OVER_TRANSPORT - configures HCI traces to be routed to the WICED HCI interface

              WICED_BT_TRACE_ENABLE    - enables WICED_BT_TRACEs.  You can also modify makefile.mk to build with _debug version of the library.

              SEND_DATA_ON_INTERRUPT   - if defined, the app will send 1Meg of data on application button push

              SEND_DATA_ON_TIMEOUT     - if enabled, the app will send 4 bytes every second while session is up

              LOOPBACK_DATA            - if enabled, the app sends back received data




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