nRF51422 Central not always detecting peripheral's beacon and ble services

RE: nRF51422 Central not always detecting peripheral's beacon and ble services

Dan K. — Fri, 22 Jan 2016 17:04:09 GMT

I also have the beacon and peripheral service working together. The problem is that on my other device, running as a central (S130), I can have periods where it seems to stop seeing the beacon advertising packets. During these periods, the Master Control Panel shows both the beacon and the service, but as the debug log below shows, my central scanner doesn't pick up the beacon. It was much worse when the BLE service was advertising more frequently (480ms vs. 2000ms). My application relies on being able to pick up the beacon at least every 20 seconds, but during these periods, it can go > 30 seconds without registering the beacon.

(Most of the time both beacon and BLE service are found)
[11:45:23] Beacon identified: M: 13330 m: 30806 P: -61
[11:45:24] Beacon identified: M: 13330 m: 30806 P: -61
[11:45:25] BLE service identified
[11:45:26] Beacon identified: M: 13330 m: 30806 P: -61
[11:45:26] Beacon identified: M: 13330 m: 30806 P: -61
[11:45:27] BLE service identified
[11:45:28] Beacon identified: M: 13330 m: 30806 P: -61
[11:45:28] Beacon identified: M: 13330 m: 30806 P: -61
[11:45:30] Beacon identified: M: 13330 m: 30806 P: -61
[11:45:31] Beacon identified: M: 13330 m: 30806 P: -61
[11:45:31] BLE service identified
[11:45:33] Beacon identified: M: 13330 m: 30806 P: -61
[11:45:33] Beacon identified: M: 13330 m: 30806 P: -61
[11:45:34] BLE service identified
[11:45:35] Beacon identified: M: 13330 m: 30806 P: -61
[11:45:36] Beacon identified: M: 13330 m: 30806 P: -61
[11:45:36] BLE service identified
[11:45:38] Beacon identified: M: 13330 m: 30806 P: -61
[11:45:39] BLE service identified
...
(Periodically, the beacon stops being found by the central)
[11:51:23] Beacon identified: M: 13330 m: 30806 P: -61
[11:51:24] BLE service identified
[11:51:25] Beacon identified: M: 13330 m: 30806 P: -61
[11:51:26] BLE service identified
[11:51:28] Beacon identified: M: 13330 m: 30806 P: -61
[11:51:29] BLE service identified
[11:51:33] BLE service identified
[11:51:35] BLE service identified
[11:51:38] BLE service identified
[11:51:40] BLE service identified
[11:51:43] BLE service identified
[11:51:45] BLE service identified
[11:51:49] BLE service identified
[11:51:51] BLE service identified
[11:51:54] Beacon identified: M: 13330 m: 30806 P: -61
[11:51:56] BLE service identified
[11:51:57] Beacon identified: M: 13330 m: 30806 P: -61
[11:51:59] BLE service identified
[11:51:59] Beacon identified: M: 13330 m: 30806 P: -61
[11:52:02] Beacon identified: M: 13330 m: 30806 P: -61
[11:52:03] BLE service identified

RE: nRF51422 Central not always detecting peripheral's beacon and ble services

Petter Myhre — Thu, 21 Jan 2016 09:33:27 GMT

Seems to be working fine here. I tested with SDK 10.0.0 on PCA10028. I just added a app_beacon_start() after ble_advertising_start(). I didn't modify the intervals in the example, 400 ms for the beacon, and 480 ms for the hrs.

Here is the sniffer trace.

RE: nRF51422 Central not always detecting peripheral's beacon and ble services

Dan K. — Wed, 20 Jan 2016 15:48:25 GMT

I'm only calling ble_advertising_start() once to start advertising the ble service. I'm using the app_beacon_start() function in advertiser_beacon.c taken directly from the examples to start the beacon, which I believe is using timeslots to provide both the beacon and ble service advertising effectively simultaneously.

RE: nRF51422 Central not always detecting peripheral's beacon and ble services

Petter Myhre — Wed, 20 Jan 2016 14:25:49 GMT

I don't understand. You can only have one advertisment running at the time. If you try to call sd_ble_gap_adv_start() when you are advertising, it will return error 0x00000008 = NRF_ERROR_INVALID_STATE

RE: nRF51422 Central not always detecting peripheral's beacon and ble services

Dan K. — Tue, 19 Jan 2016 21:13:12 GMT

Initially, the beacon was advertising at a 480 ms interval, and the connectable service at 400 ms. Changing this to 500 ms and 2000 ms, respectively, at least allowed me to see both, but not always reliably. The beacon and ble service are running simultaneously, and the advertising timeout is 0 (always advertising). Supervision timeout is 40 sec and slave latency is 0. The scan interval is 100 ms and scan window is 50 ms.

RE: nRF51422 Central not always detecting peripheral's beacon and ble services

Petter Myhre — Mon, 18 Jan 2016 10:57:06 GMT

What are your advertising intervals, what are you timeouts, and when do you change between doing connectable advertising and non-connectable advertising? What is you scan window and scan interval?