Central: multiple connection at the same time

[Thierry]

Hi,

I'm using S130 with PCA10028 and I would like to connect my central device to multiple peripheral at the same time.

According to my understanding, the only way I have to achieve this goal is to use whitelist. However, once the first device acknowledge my connect, scanning seems to stop and no more connections are done.

Is my understanding correct ? and if yes why ? Where come from this limitation ? (SDK, Bluetooth, hardware...)

Does I have any way to continue connection on other devices without recalling sd_ble_gap_connect again ?

Thanks for your support

[Petter Myhre]

This is just how it is implemented in the SoftDevice, it will connect to the first device found in the whitelist then it will stop scanning. Then you can for example call sd_ble_gap_connect() again when you get the BLE_GAP_EVT_CONNECTED event.

There is no limitation on this, it could have been implemented the way you describe, but it is not. I will add this as a feature request/improvement internally.

[Petter Myhre]

As long as one follows the timings in the spec, I guess one can implement a solution where a new connection request is sent in the window between the previous connection request and the transmitWindowSize (here the radio is in RX and busy). But you would actually need to receive an advertising packet and send a connection request in this window. So in short, Nordic's implementation is to establish one connection at the time, establishing two connections by may or may not be possible, I don't know.