Receving advertisement packets in scanner problem

RE: Receving advertisement packets in scanner problem

Sigurd — Mon, 29 May 2017 07:44:32 GMT

app_timer_cnt_get() returns the current value of the RTC1 counter.

What kind of functionality are you looking for? A type of stopwatch/time taker function? or time elapsed since program startup?

RE: Receving advertisement packets in scanner problem

mani — Wed, 24 May 2017 12:01:29 GMT

ok. what does this function returns app_timer_cnt_get().how can i calculate time from this function in one second.

RE: Receving advertisement packets in scanner problem

Sigurd — Wed, 24 May 2017 11:37:17 GMT

Q: how can i calculate numbers of ticks does ble_app_hrs_c example can generate in one second

A: You can use the function APP_TIMER_TICKS(..). If you call the function with APP_TIMER_TICKS(1000,APP_TIMER_PRESCALER) it will return the number of ticks for 1000 ms(=1 second).

The app timer uses the RTC timer, which have a frequency of 32768 Hz. So it wil generate 32768 ticks in 1 second.

RE: Receving advertisement packets in scanner problem

mani — Wed, 24 May 2017 10:33:13 GMT

Thanks very much .this information is very useful to me.

one more question ,how can i calculate numbers of ticks does ble_app_hrs_c example can generate in one second.by using this function app_timer_cnt_get(); iam able to receive ticks.by using this how can i calculate the time in seconds only??? by the way iam using nrf51822 Dk.

RE: Receving advertisement packets in scanner problem

Sigurd — Tue, 23 May 2017 13:54:48 GMT

Note that the ble_app_beacon example is meant to be a pure beacon, where it only does advertising. If you want to connect to the central(in order to e.g. send information from the central to the beacon), I would not recommend using the ble_app_beacon example, but instead use e.g. the experimental_ble_app_blinky example for your peripherals("beacons").

RE: Receving advertisement packets in scanner problem

Sigurd — Tue, 23 May 2017 13:35:06 GMT

Yes, by default the ble_app_multilink_central example will try to connect to all peripherals that are named "Nordic_Blinky". (it will look for the name in the on_adv_report() function). It will continue to scan and connect until it have connected to the number of peripherals defined by CENTRAL_LINK_COUNT. By default this is set to 8, but can be increased to 20. The CENTRAL_LINK_COUNT is the number of central links used by the application. When changing this number remember to adjust the RAM settings
Yes, the central will scan on all 3 advertising channels (37,39 and 39). When you send an advertising packet from the peripheral, the peripheral will actually send the packet on all 3 advertising channels. It will first send it on channel 37, then on 38 and then on 39.

RE: Receving advertisement packets in scanner problem

mani — Tue, 23 May 2017 12:41:47 GMT

Thanks for information. In my project iam using central as ble_app_multilink_central example and peripheral as bel_app_beacon example. Iam receiving the multiple peripheral uuid's and some data from this function on_adv_report(p_ble_evt) located under [BLE_GAP_EVT_ADV_REPORT case] in [ble_app_multilink_central] example.I have to use only this [BLE_GAP_EVT_ADV_REPORT case] while receive the uuid and some data.

My question is ,by doing above modification in source code ,do this central example is still connects to the multiple peripherals ??

Do this central scans on a different advertising channel when the packet is sent??

RE: Receving advertisement packets in scanner problem

Sigurd — Tue, 23 May 2017 12:02:20 GMT

Yes, the ble_app_multilink_central will continue to scan for advertising packets, even when connected to other peripherals. When only doing advertisement, there is a small chance that an advertisement packet is lost, since the central might be scanning on a different advertising channel when the packet is sent. So if you need that no packets are dropped, you will need to connect with your "beacons" to the central.

In a connection, Bluetooth low energy uses CRC and the packet contains a sequence number and next expected sequence number to ack/nack a packet. Every packet will be acknowledged at the link layer, so if there isn't an acknowledgement, the packet will be retransmitted.

RE: Receving advertisement packets in scanner problem

mani — Tue, 23 May 2017 11:54:07 GMT

Thanks for replay. Do this ble_app_multilink_central example can receive multiple beacons advertisement packets without any loss in central ??do i need to modify anything??

RE: Receving advertisement packets in scanner problem

Sigurd — Tue, 23 May 2017 11:25:30 GMT

Please let me know if anything is unclear, or if you have other questions.

RE: Receving advertisement packets in scanner problem

Sigurd — Tue, 23 May 2017 10:53:58 GMT

Hi,

If you want to connect to the “beacons” from a central, I would instead recommend using the ble_app_multilink_central example as the central. With this central example, you should be able to connect to up-to 20 peripherals/beacons. For the “beacons” you can use the BLE Blinky Application (experimental_ble_app_blinky).