Help with understanding advertising choices

RE: Help with understanding advertising choices

Keith Brafford — Tue, 22 Oct 2019 21:56:24 GMT

I finally figured out how to add a scan response packet with the ble_advertising module, so I just moved the entire device name by itself there. I also made the appearance field optional, so I can steal those bytes back if I need them. It was actually a lot easier than I was making it out to be earlier.

// remove the device name from the main advertising packet
//init.advdata.name_type = BLE_ADVDATA_FULL_NAME;
//init.advdata.include_appearance = true;
init.advdata.flags = BLE_GAP_ADV_FLAGS_LE_ONLY_GENERAL_DISC_MODE;

init.advdata.uuids_complete.uuid_cnt = sizeof(m_adv_uuids) / sizeof(m_adv_uuids[0]);
init.advdata.uuids_complete.p_uuids = m_adv_uuids;

init.config.ble_adv_fast_enabled = true;
init.config.ble_adv_fast_interval = APP_ADV_INTERVAL;
init.config.ble_adv_fast_timeout = APP_ADV_DURATION;
init.evt_handler = on_adv_evt;

init.srdata.name_type = BLE_ADVDATA_FULL_NAME;
#ifdef INCLUDE_APPEARANCE
init.srdata.include_appearance = true;
#endif

err_code = ble_advertising_init(&m_advertising, &init);

RE: Help with understanding advertising choices

Simonr — Mon, 14 Oct 2019 11:37:41 GMT

Hi Keith

Have you added any additional services that take up space in the advertising packet? I just tried the custom service project myself and I'm able to see the full name without any problems. If you add additional service UUIDs to any examples that don't use scan response packets the name will be shortened if the advertising packet is filled with UUIDs, etc. Does that help to clear things up?

I meant that it would be easier to implement the custom service(s) to the ble_app_blinky example, than adding the scan response packet implementation to the project you're already working on if the custom service(s) is the only thing you need from that project. The ble_app_blinky example still uses the ble_advertising module, so that is still the preferred module.

Best regards,

Simon

RE: Help with understanding advertising choices

Keith Brafford — Sat, 12 Oct 2019 04:44:43 GMT

Simon, I am mostly looking for clarity and understanding. For instance, I notice that ble_app_uart appears to do the same thing as the custom_ble_service_example does as far as advertising goes, yet uart gets "Nordic_UART" to show up while my version of the example only gets the first 4 characters. That is further confusing.

RE: Help with understanding advertising choices

Keith Brafford — Fri, 11 Oct 2019 21:44:45 GMT

Thanks for the responses.

So you're saying that the ble_advertising module isn't the "nordic preferred" approach? Since the ble_advertising module works well with the peer manager, I was hoping you could explain to me how I can use the module to get the desired behavior.

RE: Help with understanding advertising choices

Simonr — Fri, 11 Oct 2019 08:07:04 GMT

Hey Keith

This tutorial should be helpful for learning how to make a scan response packet, but if you're using the approach in the Blinky example anyway, I think it would be faster/easier to add the custom service(s) to that example project instead.

Best regards,

Simon

RE: Help with understanding advertising choices

Keith Brafford — Thu, 10 Oct 2019 17:54:03 GMT

Thanks for the explanation. Another difference in approaches is the custom example uses the "ble_advertising" module, but the blink app goes straight to the soft device, right? Can you help me understand what I would need to do to make the ble_advertising module behave like the blinky approach (i.e. put the full UUID in the scan response)? Or is it just better to not use that module if you want to do this?

RE: Help with understanding advertising choices

Simonr — Thu, 10 Oct 2019 09:19:45 GMT

Hi Keith

The main difference between your advertising init and the one in my colleague's example is that he has included the UUID in his advertising packet, while your alternative includes this UUID in the scan response packet. The UUID takes up quite a few of the 29 bytes available in an advertising packet, which is why there is less room for the device name in the example. So you could move the UUID into the scan response packet instead of the advertising packet instead, and you should have room for a longer device name in the example as well.

Best regards,

Simon