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CCS/CC2652RB: Advertisement sequence (38, 38, 39) or (39, 38, 39) instead of (37, 38, 39)

Damien BOSCA
Intellectual 560 points
Part Number: CC2652RB

Tool/software: Code Composer Studio

HI,

I start with the BLE stack, I usually use directly the commands of the RF drivers, but for my new project I need the BLE stack.

Also I have an LP-CC2652RB card (without crystal) and I compile with CCS v9.3.0 the simple peripheral project coresponding to this card (with SDK 4.10.00.78).

It works wonders and it's great to see it without using quartz with excellent stability. but i noticed one thing i don't understand about advertisements:
for this test I deactivate all my Bluetooth devices, I only have one 'scanner' in function that I did myself with 3 CC2642R1F in parallel on SPI bus, each passively scan only one channel with infinite time (chanel 37, 38 and 39) by accessing directly by the rf driver command.

So, now, when I powerup LP-CC2652RB board with simple peripheral project programmed on it, the first thing is that the board will advertise on channels 37 38 and 39. but half the time, the sequence is not respected, and device scan following a curious sequence: one time: 37, followed by 38 and by 39 (this is normal) and after i have this abnormale sequences  (38, 38,39) or (39,38,39)  that doesn't stop until I make a connection with a central. In fact the advertisement on the first channel  (37) seems to be randomly replaced by a advertisement on channel 38 or 39.

Bellow some screenshot of my passive scanner.

Normale sequence (37, 38, 39):

1st case: after one normal cycle (37, 38, 39) it going to abnormale sequence (38,38,39) and stay with:

2nd cases: after one normal cycle (37, 38, 39) it going to abnormale sequence (39,38,39) and stay with:

I can confirm the results with a different second scanner that I had done before.
I can also confirm that I do not receive any ads on channel 37 (after the first and the only one sended) otherwise the LEDs directly controlled by the scanner receiver (CC2642R1F) would flash.

I can also confirm that channel 37 of my scanner is active and functional because it responds correctly to advertisement that I can send to test with another device.

Do you have any idea what might be going on?

Other things:
By coupling an RF detector to my oscilloscope, I can clearly see the 3 legacy advertisements, I also see 4 bursts which must correspond to the second set of Advertisements. why 4?

Note:
I read that the LP-CC2652RB board are equipped with a preliminary version of the chip, on my board I have the following version:

Best Regards,

Damien.

  • 0
    TI__Guru 56590 points

    Hello Damien,

    I have assigned an expert to comment.

    What is the version numbers on the launchpad?

    Have you tested with a regular CC26x2 LP?

    Have you tested vs a third party sniffer?

  • 0 in reply to Eirik V
    Intellectual 560 points

    Hi Eirik,

    On my  launchpad I have the following sticker on it:

    -------------------------------------

    HW Rev : A

    FW: SDK2.10  

    1903

    ------------------------------------

    Note:  I reprogrammed Application Firmware with 'simple peripheral project' / SDK 4.10.00.78.

    I don't test on regular CC26x2RB I don't have one, however I'm going to add the BLE stack on my device which includes a regular CC2642R1F. I'll see what it looks like but it's still different.

    With 'BLUEPIXEL BLE Scanner' (like in the SDK tutoriel), launchpad working fine. but in case I am not mistaken, not advertising on channel 37 just can add a latency when we want to connect the device, and no more repercussion. So we can't highlight this issue with this type of scanner but only undergo it.

    To see the issue, this require passive scanner and better  if it can scan the 3 channels at parrallele (not splitted in windows time slot), and upload raw data with chanel ID.

    I just saw that there are sniffers BLE which can be interesting, but I trust mine which use for the first version: 3  x CC2640F128 with the command 'CmdBleGenericRx', and for a second version: 3 x CC2642R1F with the command  'CmdBleGenericRx'  or 'BLE_cmdScan' in passive mode. For each chanel i have 1 led drived directly by each receiver RF callback and for channel 37 they remain off. I am well aware that it could come from a bug on my part, some are very vicious, but I'm pretty sure of myself.

    But the phenomenon appears and remains about half the time after turning on the launchpad and without connecting it to a central.
    after connecting it to a central, the cycle returns to normal.

    Best Regards,

    Damien.

  • 0 in reply to Damien BOSCA
    Intellectual 560 points

    I just make new CCS workspace and import 'Simple peripheral' for CC26x2R1 device.

    as is, I programed it in my  own board embeding a commercial CC2642R1F chip.

    I have exacly the same phenomenon:

    after cycling power, once in two, channel 37 is not advertised in the cycle, it is replaced either by a advertisement on channel 38 or a advertisement on channel 39.

    every time, after having connect it with for example 'BLUEPIXEL BLEScanner', I immediately find a normal cycle (37, 38, 39)

  • 0 in reply to Damien BOSCA
    Intellectual 560 points

    By limiting the number of connections to 1 (MAX_NUM_BLE_CONNS = 1), the chip stops advertising when it is connected, and restarts again when it is disconnected. we then find the same phenomenon randomly on reconnection.

    On the other hand I found what is for me the solution: I deactivate the second type of advertisements (long range), at this time the operation is perfect, I had to do more than 50 tests (connect/deconect) with in my program a notification sent automatically every second on the 4th characteristic, then all is really reliable and consistent with my scanners and with my scope.

    By dint of making manipulations, apparently it is really the first legacy advertising channel which is altered. sometimes the first pack of 3 advertisement is good and it is afterwards altered permanently until the advertisements are reenabled or reconfigured by the commands: "GapAdv_enable", and after this, it can be realtered again or not. I think (not sure) that is the switching of radio mode or the switching  of advertisements set that causes this.

  • 0 in reply to Damien BOSCA
    TI__Expert 5345 points

    Damien,

    This is all great information. Thanks for all the details. 

    It seems to me that you resolved your issue, but found a bug on our stack.

    If that is the case, I will submit all the details to our dev team in order to get the defect fixed. If your issue is resolved, please mark the thread as "This resolved my issue". Otherwise, please let me know if you have questions still open.

    Thanks,

    Luis

  • 0 in reply to Luis M
    Intellectual 560 points

    Thanks for your Feedback Luis,

    In my actual application, anyway I would have removed the second set of advertisements. so for me is OK.

    Best Regards,

    Damien.