nRF52840, evaluation for BLE devices to be used in a test system

[WilliamMcCoy21]

I am in the conceptual stages of development for a BLE test system.

The test system requires:

Fast transceiver and connection with BLE devices, preferably capable of scanning for devices in ms (5ms or lower preferably) with a high data rate (1 Mbps).

Capable of calculating the BLE channel received and controlling the BLE channel used.

Controlled modulated RF wave transmission (optional).

The test requires the capability to communicate and connect with 6 devices in parallel, is the nRF52840 capable of connecting with multiple devices?

I am planning to create a PCB using the nRF52840 chip or similar which fits the requirements. Can multiple (up to 6 depending on the number of devices that can be connected) nRF52840 dongle with PCB Altium documents provided by Nordicsemi be used on one larger PCB without interference? the BLE circuits will; share solid inner layer ground and power sources with the ground vias placed close to the pins, be located close to the edge of the PCB, be routed to avoid noise on Vcc and the area of the antennas will have a keep out area with no traces or metal near. The PCB dielectric thickness will match that of the nRF52840 dongle to prevent an effect on the antenna.

https://www.nordicsemi.com/-/media/Software-and-other-downloads/Dev-Kits/nRF52840-Dongle/nRF52840-USB-Dongle---Hardware-files-2_0_0.zip

Can an external antenna then be added to the PCB using an SWF or similar surface mount RF connector?

[Kazi Afroza Sultana]

Hello William,

Thanks for your queries.

''Fast transceiver and connection with BLE devices, preferably capable of scanning for devices in ms (5ms or lower preferably) with a high data rate (1 Mbps).''

That high data rates can be rarely achieved using BLE5.0 2MPHY but the devices needs to be very close to each other with almost no packet loss. It is impossible to achieve this with multiple links.

''The test requires the capability to communicate and connect with 6 devices in parallel, is the nRF52840 capable of connecting with multiple devices?''

Our softdevice offers a maximum of upto 20 connections, so connecting with multiple device is not a problem. 

If you use nRF5 SDK and the Softdevices, then you can find the maximum number of supported connections in the Soft device specifications, found here: https://infocenter.nordicsemi.com/topic/struct_nrf52/struct/nrf52_softdevices.html?cp=4_7. Its usually listed in the key features, see the S140 SoftDevice Specification for reference. If you use nRF Connect SDK, then you will have to take a look at the SoftDevice Controller documentation: https://developer.nordicsemi.com/nRF_Connect_SDK/doc/latest/nrfxlib/softdevice_controller/README.html#. 

but achieving that high data rates with multiple connections is almost impossible.

''The test requires the capability to communicate and connect with 6 devices in parallel, is the nRF52840 capable of connecting with multiple devices?''

The PCB design and multiple connection ability are not linked. Those are different things. If you already have your design can send to us we can check.  However having 6 radios on the same PCB at the same time, not a feasible idea. When one of them is transmitting data, none of the other will be able to receive anything. 

''Can an external antenna then be added to the PCB using an SWF or similar surface mount RF connector?''

I think it is possible to connect different antenna with connector.

Hope it helps. Feel free to ask if you have more queries.

Best Regards,

Kazi Afroza Sultana