Advertising while connected revisited

[Philip Odom]

I'm taking a look at the timeslot API example here, which was linked to in the answer to this question.

Very interesting! As I gather from the documentation for S110 and S130, it is still that case that a connected peripheral can advertise as a broadcaster while connected, but the API doesn't allow connectable advertising.

I'm trying to determine if doing so would violate the BLE spec somehow. I'm testing out this setup:

• Continue sending connectable advertisements while connected.
• Include a flag in manufacturer specific data that shows the peripheral status (busy/available).
• If available, disconnect from the current device when a different device attempts to connect.
• Ignore new connection attempts while busy.

I realize that dropping the connection and connecting to a new device would not happen on the first attempt, especially if using the TS API. But I think it would allow me to detect the connection attempt, drop the existing connection, and place my device in a state to connect to the new device.

[Petter Myhre]

So you want to do connectable advertising that can't be connected to? Doesn't sound like you are following the spec... However, the BLE spec allows having multiple connections as a peripheral, we actually have an alpha that supports this for the nRF52, see this for more information.

Could you explain a bit more about your application? What do you achieve by doing this?

[Philip Odom]

Hi, Petter. I actually want to do connectable advertising that can be connected to, even while my peripheral is already connected to a central.

I'm not trying to allow connection to multiple centrals. I just want to simplify using the peripheral with multiple centrals.

The peripheral would send connectable advertisements even while connected. We might also send status info as manufacturer-specific data indicating whether the peripheral is already connected and if it can drop the connection.

If a second central tries to connect to the peripheral, the peripheral would, depending on its state, disconnect from the first central to connect to the second.

Thanks for the link to the nRF52 project. I'll take a look at it. Supporting multiple logical peripherals could be an option, but it's not exactly what we were thinking of. And we're using the nRF51.

[Petter Myhre]

With our current SoftDevices (except the s132 4.0.0-2.alpha) you cannot do connectable advertising while you are in a connection, so I don't see how you can do what you describe.

[Roger Clark]

Philip

Why are you connecting? Is data being written to your BLE device or just being read.

If its just being read, you would be better off just putting the data into the advertisement, even if that means sending different data in each advertisement.

[Chris]

did this change with SDK 14 / SD 5.x ?