Zephyr on nordic - many questions

[Davide]

Hello, I've just found the Zephyr project which provides very interesting features and many questions are rising in my mind, but I don't know if this is the correct place to ask, let's try...

1. An open ble controller for nrf52 series is provided by Nordic. Is it derived from the controller in the nordic SDK? I mean, can I expect similar performance? (in terms of maximum packet size, maximum number of simultaneous connections, maximum number of packet per connection events)

2. I've seen that Zephyr already have drivers for 802.15.4 for the nrf52 (but I didn't tested them), can the BLE and 802.15.4 run simultaneously?

3. In Zephyr, the BLE controller part and the BLE host part are separated with the HCI interface. The host seems not to be compatible with BlueZ, can I use BlueZ as host to make the code portable to linux machines such as raspberry or even a desktop pc?

If somebody can answer one or more of these question I would be very grateful. Thank you, Davide.

[Carles]

but I don't know if this is the correct place to ask, let's try...

It's fine, although a better place would be the Zephyr mailing list: www.zephyrproject.org/.../how-to-contribute

1. An open ble controller for nrf52 series is provided by Nordic. Is it derived from the controller in the nordic SDK?

No, it's a completely different codebase.

can I expect similar performance? (in terms of maximum packet size, maximum number of simultaneous connections, maximum number of packet per connection events)

Yes, and also in power consumption. They are comparable in features and performance.

2. I've seen that Zephyr already have drivers for 802.15.4 for the nrf52 (but I didn't tested them), can the BLE and 802.15.4 run simultaneously?

Not yet, but the ticker (radio scheduler) can be used to schedule 15.4, like it does for the flash driver today.

3. In Zephyr, the BLE controller part and the BLE host part are separated with the HCI interface. The host seems not to be compatible with BlueZ, can I use BlueZ as host to make the code portable to linux machines such as raspberry or even a desktop pc?

Yes, see my blog post here:

www.zephyrproject.org/.../building-qualified-ble-controller-zephyr-os-19

The BLE controller is now qualified and we've tested it with BlueZ.

In fact I was doing that this week at ELCE in Prague: twitter.com/.../922457620597919744

Regards,

Carles

[Davide]

Thank you. I ask you a further clarification regarding the third point: what you did is to made a BLE controller that interfaces (I suppose through the serial/USB) to a host device (say a pc running linux), right? Then you are providing a solution where host and controller are two different physical devices.

I'm interested to a single device solution, where the software interface on the controller side (I mean the functions and the macros of bluetooth.h, hci.h) is the same interface provided by blueZ. I'm working on an heterogeneous network, some devices are wearables (nRF52), others are embedded processor (again nRF52, with some add-on) and also a couple of raspberrys. In such scenario being able to reuse the code as it is may be very helpful.

[Carles]

Yes, that's for a dual-chip solution.

If you want a single-chip solution you can either use Zephyr's host or else interact directly with the Zephyr controller within your application via HCI. But BlueZ is not part of Zephyr and will never be, since it requires the Linux kernel and its APIs are not compatible with an RTOS.

[Davide]

Thank you, that exactly what I wanted to know!