How to Continue Peripheral Device Advertising After the Connection of a Central Device that Peripheral Device

RE: How to Continue Peripheral Device Advertising After the Connection of a Central Device that Peripheral Device

Mark J — Thu, 26 Sep 2019 21:22:04 GMT

Thanks again Kenneth. That did the trick! increased both counts (1->2 for each) and modified RAM start (size was already 0x4000) as required to get past nrf_sdh_ble_enable(). Now, I can see advertising immediately when I disconnect using the nRF Connect app. Thanks much!

RE: How to Continue Peripheral Device Advertising After the Connection of a Central Device that Peripheral Device

Kenneth — Thu, 26 Sep 2019 20:18:57 GMT

You likely need to increase NRF_SDH_BLE_PERIPHERAL_LINK_COUNT and NRF_SDH_BLE_TOTAL_LINK_COUNT, I suspect that the sd_ble_gap_adv_start() return an error code here if you don't.

Once you do that you will likely get a warning in nrf_sdh_ble_enable() that you need to modify the RAM size required by the softdevice.

RE: How to Continue Peripheral Device Advertising After the Connection of a Central Device that Peripheral Device

Mark J — Thu, 26 Sep 2019 20:03:55 GMT

Thank you for the reply Kenneth. I have added a sd_ble_gap_adv_start() call when BLE_GAP_EVT_CONNECTED hits the ble_evt_handler(), but advertising is not restarting. I suspect that (for some reason) advertising is not permitted when a connection is made.

Any other options that I should try?

RE: How to Continue Peripheral Device Advertising After the Connection of a Central Device that Peripheral Device

Kenneth — Thu, 26 Sep 2019 12:00:13 GMT

Different applications have different requirements, so the softdevice have tried to make it as flexible as possible. You may start advertising again on the connection event, or at any time during connection if you want, there is no need to wait for the disconnect event. You may also be connected to two central devices and/or disconnect the first connection on the second connection occurs. Again it can pretty much do whatever you want, but you need to call the api for it.

I have seen some phones may keep connection even if the application is shut down or want to close connection. There is no way for the peripheral to know that this have occured, but you may for instance add some keep alive data from the app, so once the peripheral have not received any keep alive for a timeout period it may disconnect from the phone and start advertising again. Again, you are free to do this as you see fit.