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Capture/Record time when BLE transmit packet on CC2640

Peter Huang
Expert 1050 points

Hi, all expert.

How could I record the time when BLE Link Layer transmit a packet?

I want to use this time information to synchronize with master device.

Thanks.

  • 0
    TI__Mastermind 34660 points

    The best you can do is to register for a connection event callback using HCI_EXT_ConnEventNoticeCmd. You could then implement a timestamp when the callback is processed.  Of course, this is not the exact time the packet was transmitted as you need to account for connection event post-processing time and the processing time it takes to receive the connection event callback.

    See the HCI API in the appendix of the software developer's guide included with the 2.1 installer for more information on this command including an example.

  • 0 in reply to Tim C
    Expert 1050 points

    Thanks for your reply.

    I had try to use HCI_EXT_ConnEventNoticeCmd, but it dose not accurate.

    My connection interval set to 30 ms and turnoff powerSaving.

    There are some experiment data (ticks) below:

    connection event1     T1 time       connection event2    connection event3      T4 time

    79124,                       82152,         82176,                      85121,                         88185,

    88213,                       91151,         91173,                      94118,                         97185,

    Slave record T1 time in simpleProfile_ReadAttrCB() when Master read Char2 .

    Slave record T4 time in simpleProfile_WriteAttrCB() when Master write Char1.

    We can know time between connection events is almost 3000 ticks(=30 ms).

    But, it seems that Slave record T1 time before record connection event2 time.

    It is a little weird.