Is the Zephyr BLE Controller (BT_LL_SW_SPLIT) Supported on nRF54L15 DK?

[jwieme]

I’m trying to use the Zephyr software split BLE controller (BT_LL_SW_SPLIT) on the nRF54L15 DK with NCS 3.0.1. I understand that this controller is not certified, but I would like to implement controller level changes, which is not possible with the Nordic Controller.

The ISO Broadcast example (https://github.com/zephyrproject-rtos/zephyr/tree/main/samples/bluetooth/iso_broadcast) works perfectly fine with the Nordic controller, but when I run it with the SW-split controller snippet (bt-ll-sw-split + conf file), it immediately triggers a stack overflow. From the build output, I can see that the Zephyr controller is compiled and included, so it’s definitely running the SW-split controller and not the Nordic SoftDevice. I’ve attached a screenshot of the output.

Has anyone successfully run BT_LL_SW_SPLIT on the nRF54L15 DK, or is it not possible/supported yet?

[Håkon Alseth]

Hi,

 

You are seeing a stack overflow, as the assert log indicates.

You can check your map file (build/app-name/zephyr/zephyr.map) and search for the faulting thread address (take away the 0x prefix, as host is 64 bit)

 

Or you can enable CONFIG_THREAD_NAME=y and it will print the name in the assert output.

 

Kind regards,

Håkon

[jwieme]

Thanks for pointing this out, the faulting thread originate from zephyr/kernel/libkernel.a(system_work_q.c.obj) for k_sys_work_q. To resolve this I simply increased the work queue stack in prj.conf with CONFIG_SYSTEM_WORKQUEUE_STACK_SIZE=2048. Additionally I was able to verify that the Broadcaster is operating with the zephyr based controller through some LOGGINGS in the HCI controller code.