Extended Advertising - reception and data size

Hi,

I recently started with nRF52840-DK, Zephyr and nRF Connect SDK (v. 1.9.1). I want to test extended advertising. Since there is no example of "pure" extended advertising (i.e. no periodic), I modified the periodic_adv example. Modification is quite easy: In prj.conf setting CONFIG_BT_PER_ADV=n, in main.c skipping bt_le_per_adv_set_param() and bt_le_per_adv_start(), usage of bt_le_ext_adv_set_data() instead of bt_le_per_adv_set_data(). Now extended advertising runs well. With a Sodera sniffer, I can see three ADV_EXT_IND frames in channels 37/38/39, followed by an AUX_ADV_IND frame in one of the data channels. The AUX_ADV_IND frame contains two AD elements: One with the data I want to transmit and one with the complete local name as set in prj.conf.

For reception, I use the periodic_sync example, which should support extended advertising without the periodic functionality too.

Now the questions:

My receiver calls the scan_recv function, but always I see only one of the AD elements. The buffer contains only the AD element with the local name, which is the last one in the frame (according to the sniffer raw data). There is no indication of the reception of my data in the second AD element. What have I to do to receive both (or even more) AD elements? What is the intention here - to have several calls of scan_recv for every AD element or to have a list of buffers or something else?

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  • Hi Simonr,

    that's what I'm telling from the beginning - I can send more data than I'm able to receive. I'll attach a sniffer data file (Sodera sniffer), from my extended advertising max data tests - here "pure" extended advertising is used, no periodic functionality.

    Capture_test-extended-adv_maxdata.cfa

    The AD element in the AUX_ADV_IND contains 227 data bytes [0xff, 0xff, 0x00, 0xaa, 0x00, 0x01, 0x02 ... 0xde], which is the maximum I can receive - as I mentioned, net_buf_simple_max_len = 229 (227 + size + type).This is the simple extension from the advertising example, including two byte manufacturer ID.

    On Tx side, I can extend the data to 249 bytes in total (counting up to 0xf4), which I can see correctly sent in the sniffer. How I can extend the reception data size to that number?

    I'm using Nordic nRF52840-DK for Tx as well as for Rx, I program both devices using the same environment. I don't expect any problem from that side.

    Additional question: On advertiser side, is there any possibility to have a call-back function to be informed once the AUX_ADV_IND frame is transmitted?

    Best regards

    Axel

Reply
  • Hi Simonr,

    that's what I'm telling from the beginning - I can send more data than I'm able to receive. I'll attach a sniffer data file (Sodera sniffer), from my extended advertising max data tests - here "pure" extended advertising is used, no periodic functionality.

    Capture_test-extended-adv_maxdata.cfa

    The AD element in the AUX_ADV_IND contains 227 data bytes [0xff, 0xff, 0x00, 0xaa, 0x00, 0x01, 0x02 ... 0xde], which is the maximum I can receive - as I mentioned, net_buf_simple_max_len = 229 (227 + size + type).This is the simple extension from the advertising example, including two byte manufacturer ID.

    On Tx side, I can extend the data to 249 bytes in total (counting up to 0xf4), which I can see correctly sent in the sniffer. How I can extend the reception data size to that number?

    I'm using Nordic nRF52840-DK for Tx as well as for Rx, I program both devices using the same environment. I don't expect any problem from that side.

    Additional question: On advertiser side, is there any possibility to have a call-back function to be informed once the AUX_ADV_IND frame is transmitted?

    Best regards

    Axel

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