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  • Case ID: 329545
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30 simultaneous BLE peripherals connections. Known solutions? nRF52840 Dongle?

FGranados

Hi,


we are developing a solution where the number of peripheral BLE devices is increasing and we need to manage up to 30 realiable connections. We have been working with a nRF52840 USB Dongle having up to 8 connections with a good performance.

In our app, we are interacting with the dongle using a python library called Blatann, which is implemented also over the NordicSemiconductor github repo pc-ble-driver-py. We had some trouble with the memory the dongle can provide, since it is highly related to BLE parameters such as, MTU packet size, number of connections, etc. We tried to find some relevant information about this topic, but we only found that BLE is designed to support a high number of simultaneous connections, but we do need more details.

Could you provide some more info regarding these simultaneous connections or recommend any Nordic solution from the company or any third-party that uses your chips? It does not need to be the nRF52840, we are open on this side.

ADDITIONAL INFO

We flashed the USB Dongle with the FW recommended by Blatann (usb_with_s132).

According to this followin table, the number shows the softdevice and the quantity of multiple simultaneous connections available.

 

Thanks in advance!

  • 0

    Hi,

    Solutions built on pc-ble-driver are somewhat limited, in that pc-ble-driver itself has some limitations. As you already mention, memory usage is highly dependent on what features are used, and their configurations. Therefore some choices has been made in the connectivity firmware, to cover a wide range of use cases, but given finite resources some tradeoffs have been made.

    If you want to continue down the route of using pc-ble-driver, then you might be able to get a better configuration (for your use case) through modifying the connectivity firmware. The firmaware is built on the serialization example from nRF5 SDK with a patch applied. Information (and patches) are found as part of the pc-ble-driver project on github.

    For PC applications using an nRF device for BLE connectivity, one option going forward (away from pc-ble-driver) is to equip the nRF device with the Bluetooht: HCI USB sample from nRF Connect SDK, You then need a Bluetooth LE Host stack on the PC side.

    Please note however that the absolute maximum number of connections, whether using something based on the SoftDevice and nRF5 SDK (such as pc-ble-driver), or based on the newer SoftDevice Controller with nRF Connect SDK, is still 20 concurrent connections.

    Regards,
    Terje

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