NFC Issue

RE: NFC Issue

Roei — Wed, 20 Feb 2019 07:38:11 GMT

Thanks!!

RE: NFC Issue

tesc — Tue, 19 Feb 2019 16:40:37 GMT

Hi,

That sounds about right, yes.

Regards,
Terje

RE: NFC Issue

Roei — Tue, 19 Feb 2019 15:13:38 GMT

Ok, so I understand that this is the flow:

Central using NFC for connection ---> Peripheral is waked up and advertising ---> Central is sending a request for a connection ---> Central and peripheral and handshaking --->Connection established.

Am I right?

RE: NFC Issue

tesc — Tue, 19 Feb 2019 14:44:10 GMT

Hi,

You do not use NFC for connecting. If you use NFC during the connection then it is only for sending a short code which is used for encrypting the rest of the pairing / bonding procedure.

When a device advertises that it is connectable, it will listen for a short period of time after each advertisement is sent out, and in this short period it can receive connection requests from centrals. This is the way establishing a BLE connection works, and it is the same no matter if the devices have previously bonded or not.

For getting more familiar with BLE, please have a look at our Bluetooth Low Energy tutorials.

Regards,
Terje

RE: NFC Issue

Roei — Tue, 19 Feb 2019 14:21:45 GMT

I thought that the meaning of advertising is broadcasting my details, so other devices will know about me and have the option to connect to me. I don't understand how advertising is necessary if I try to connect to a peripheral directly with NFC, or if I was already connected and I want to connect again, while I already know the peripherals details. Maybe I didn't understand it correctly. Can you please try to clarify it?

Thanks again!

RE: NFC Issue

tesc — Tue, 19 Feb 2019 13:36:57 GMT

Hi,

In order to reestablish the connection at a later stage, you will always have to start by advertising.

You can use directed advertising in order to advertise to one particular device only, and whitelisting to only allow connections from one device or a short list of given addresses.

Regards,
Terje

RE: NFC Issue

Roei — Tue, 19 Feb 2019 13:26:48 GMT

Thanks, Terje!

Another question, regarding advertisement:

After the peripheral is connected and bonded to other central, I need the peripheral to disconnect from the central at a specific point. After that, I want to give the central the option to connect again. Do I have a way to do it, besides advertising again?

RE: NFC Issue

tesc — Tue, 19 Feb 2019 13:12:16 GMT

Hi,

Yes, that is normal.

You can use NFC field detection for waking up the device, but you still have to follow the normal procedure for establishing a BLE connection.

In order to initiate a BLE connection, the peripheral needs to advertise and the central needs to scan for those advertisements. NFC can then be used for out of band communication at a later stage in the connection procedure.

Regards,
Terje