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CC2564 Channel Mapping

Mark Ackerson
Genius 10190 points
Other Parts Discussed in Thread: CC2564

Customer is updating the CC2564 channel map to avoid the channels containing interference. According to the Bluetooth spec, there isn’t any interference avoidance behavior that is explicitly required aside from allowing the application to update the channel map proactively. We are wondering what the specific behavior is of the Bluetopia stack on the CC2564 related to the channel map. Does the link layer proactively monitor for interference and update the channel map automatically? Or, are channel map updates entirely the responsibility of the application code? Without explicitly specifying the suggested channel map from the application level, should we have any expectation of the CC2564 to avoid channels containing interference?

Please advise.

Thanks,
Mark

  • 0
    TI__Mastermind 29291 points
    Hi Mark,

    The Bluetopia stack or any other BT stack does not handle the link layer and baseband level channel hopping/elimination. All of this is handled in the CC2564 itself. Your description refers to the AFH (Adaptive Frequency Hopping) of the CC256x. The AFH will automatically avoid the interference and update the channel map accordingly. Application code does not have control over this and I think it is for a good reason.

    Hope this answers all the queries.

    Best regards,
    Vihang
  • 0 in reply to Vihang Parmar
    TI__Genius 10190 points
    Customer was under the impression that the AFH functionality was completely contained by the link layer but based on some questionable empirical performance, we wanted to confirm how this functionality was implemented. Also, while the BT stack does not control the channel hopping and elimination, there are HCI functions (HCI_Set_AFH_Host_Channel_Classification and HCI_LE_Set_Host_Channel_Classification) which allow the application code to suggest the elimination of certain channels based on external information. Should we except these functions to work as expected? Or, do these functions only work when AFH is disabled?

    Thanks,
    Mark
  • 0 in reply to Mark Ackerson
    TI__Expert 5295 points

    Hi,

    You should expect these functions to work. Assuming the host has external reliable information, it can share this information with the controller, so the controller will generate a map based on that information.

    If AFH is disabled, then it will have no meaning, as the controller will not send any AFH LMP messages to the peer device.

    Regards,

    Tomer