FEM - Front End Module Management

[eboris]

I am investigating using a front-end module with a nRf52840 in an 802.15.4 application. I have seen the 802.15.4 stack in the nRF5_SDK_15.3.0_59ac345 SDK. It looks like there is a FEM manager in the nRF5_SDK_for_Thread_and_Zigbee_v3.2.0_9fade31 SDK . CAn I copy in the FEM manager from the Thread SDK and use it with the 802.15.4 stack? Or do I need to come up with a homebrew solution?

[eboris]

Hi Bjorn - 

I think I need to provide some further information. Yes - I am referring to the 802.15.4 driver. I agree - it looks like there is a FEM manager API in the documentation.

Specifically - I am looking at the example project: nRF5_SDK_15.3.0_59ac345\examples\802_15_4\wireless_uart\raw\first . It uses a pre-compiled library - 802_15_4_lib_gcc.a   Is this the 'driver' that you are referring to? I was looking through the project for some of the API's that are shown in the 802.15.4 driver documentation and they don't seem to be present. This makes me think that this is not the driver that you are referring to -or- I am really confused. Ideally I would like to get the wireless UART example working using the 802.15.4 driver using a FEM. What am I missing? Is there a similar example project that uses the 802.15.4 driver with the FEM manager?

Thanks for your help.

eboris

[bjorn-spockeli]

Hi eboris, 

the wireless UART example in the nRF5 SDK uses the IEEE 802.15.4 stack, which has its own Radio abstraction layer. 

The 802.15.4 driver is a part of the nRF5 SDK for Thread and Zigbee so its a different SDK. To get the same functionality as the IEEE 802.15.4 stack you would have to implement a MAC layer on top of the RADIO layer I think. 

I am not aware of any example that uses the FEM or that implements the wireless UART using the 802.15.4 radio driver. 

[eboris]

Hi Bjorn - 

Ok - I had to read your response a couple of times before I realized what you were saying. I think that what I need is to follow the other path. That is:

    1) Use the IEE 802.15.4 stack (not driver) as provided in SDK 15.3

    2) Add the equivalent of a FEM controller to that stack.

    3) Then be able to use the existing example Wireless UART project (Provided in the SDK 15.3) to demonstrate the functionality that we need.  

Is that possible? Do we have access to the source code for the IEEE 802.15.4 stack so that we can insert FEM control into it? 

[bjorn-spockeli]

eboris said:

Is that possible? Do we have access to the source code for the IEEE 802.15.4 stack so that we can insert FEM control into it? 

I'm afraid we do not have the source code as its a 3rd party MAC layer from Luxoft.

[eboris]

Hi Bjorn -

We have been discussing other possibilities to solve our problem of using a 802.15.4 protocol with a nRf52840 and a FEM. We are looking for an approach to take for integrating the FEM control into the firmware.

First I wanted to ask: Could you recommend an approach on how we could solve the problem of integrating the FEM control with the 802.15.4?

The possibilities that we came up with are:

1) Use a PPI event from when radio turns ON to Tx to initiate an action on a GPIO pin that would turn the PA of the FEM. Likewise an Rx event would create a PPI event to initiate and action on another GPIO pin that would turn the LNA ON. 

2) Use the 802.15.4 stack in Zephyr. Modify the Zephyr stack to add the FEM control. 

3) Use the 802.15.4 DRIVER and the FEM manager directly. Build a MAC layer on top of that.

Any thoughts or recommendations that you can provide would be helpful.

eboris

[bjorn-spockeli]

Hi eboris,

Apologies for the late reply.  

I posted a reply in the other ticket you created on this, https://devzone.nordicsemi.com/support-private/support/237886. 

Best regards

Bjørn