[NRF51822] How to set device to Non-discovery Mode?

RE: [NRF51822] How to set device to Non-discovery Mode?

SH — Sun, 27 Jul 2014 06:46:24 GMT

A general question? What is the use-case where a BLE device will send an advertisement packet when in non-discoverable mode? I.e what is the point in doing this since technically there is no discovery procedure to look for advertisements in which limited discoverable mode is not set and general discoverable mode is not set.

RE: [NRF51822] How to set device to Non-discovery Mode?

julian — Mon, 28 Apr 2014 15:33:48 GMT

Thanks for the reply, What I observe is after bonding, Master can connect without scan, but slave have to advertising, if no advertising, master can't connect as well, seems contradict with http://stackoverflow.com/questions/22097079/is-it-possibile-to-wake-up-a-deep-sleep-ble-device-in-android-sdk since we want to save slave's power, I wonder, is it possible the other way, which is slave doesn't need to advertising?

RE: [NRF51822] How to set device to Non-discovery Mode?

Ole Morten — Mon, 28 Apr 2014 11:25:34 GMT

This is really a separate question and would be better off separately. However, there isn't really any conceptual difference between General discoverable and Limited discoverable advertising; they are just different modes defined by the spec. You can read about these in Volume 3, section 9.2.3 and 9.2.4.

Some devices may be using this flag to determine whether or not a device should be shown in a list of discovered devices.

If a device isn't advertising, it's impossible for any Central to connect to it. See this question for details: http://stackoverflow.com/questions/22097079/is-it-possibile-to-wake-up-a-deep-sleep-ble-device-in-android-sdk

RE: [NRF51822] How to set device to Non-discovery Mode?

julian — Thu, 24 Apr 2014 18:29:50 GMT

what's difference between General Discoverable and Limited Discoverable? and if no advertising, but we have bond before, can phone side do direct connect to nrf51822?

RE: [NRF51822] How to set device to Non-discovery Mode?

Ole Morten — Mon, 17 Feb 2014 11:53:37 GMT

All advertising packets can be received by any scanner, and it is hence up to the filtering done on the scanner to decide whether or not a device is shown. Even when advertising with just BLE_GAP_ADV_FLAG_BR_EDR_NOT_SUPPORTED (neither Limited nor General discoverable), some scanners may choose to show this device when scanning, and there isn't anything you can do to avoid this. This is what's called "Non-discoverable Mode" in section 9.2.2 in Volume 3, Part C of the Core Specification.

RE: [NRF51822] How to set device to Non-discovery Mode?

Terry — Mon, 17 Feb 2014 05:06:56 GMT

Thank you for your reply. I mean, if there's a way to make host can connect to my nrf51822 device, and also to make nrf51822 device not be displayed in the ble device list of host? BTW, if I use BLE_GAP_ADV_FLAG_BR_EDR_NOT_SUPPORTED to set advertising data, what mode is my device actually in? I try to do this, It can still be displayed in MCP.

RE: [NRF51822] How to set device to Non-discovery Mode?

Ole Morten — Thu, 13 Feb 2014 16:35:13 GMT

What exactly do you mean by "non-discovery mode"?

If you just mean to send advertising packets, but not be neither General Discoverable nor Limited Discoverable, this is done just by not using those flags when setting the advertising data, i.e. using BLE_GAP_ADV_FLAG_BR_EDR_NOT_SUPPORTED and not BLE_GAP_ADV_FLAGS_LE_ONLY_LIMITED_DISC_MODE or BLE_GAP_ADV_FLAGS_LE_ONLY_GENERAL_DISC_MODE.

However, if you mean to not send advertisement packets at all, you'll have to either explicitly stop advertising using sd_ble_gap_adv_stop() or wait for a timeout, and in this case, no device will be able to connect to you.