hci uart sample asserts

RE: hci uart sample asserts

Simonr — Mon, 27 Jul 2026 12:48:24 GMT

What SDK version are you using when you see this issue?

I think the next assertion in the prepare path when the LLL tries to insert the next radio event into its prepare pipeline and finds the state inconsistent, so the controller isn't able to keep up with radio event scheduling.

This could be a number of things, listed from most to least likely:

Interrupt/CPU latency starving the LLL due to a critical section blocking it (long flash writes, drivers with incorrect priority holding IRQs disabled, heavy logging in interrupt context).
Scheduling overload. There are too many concurrent roles for the timing. Nordic's scheduling documentation explains that radio timing events are time-multiplexed and collisions get rescheduled. This could be it if you have many simultaneous connections or adv/scan/connection events packed tightly collide and the pipeline can't be maintained.
Clock/HFXO problems. If you have a custom board with an incorrectly loaded HFXO clock this could assert.
Insufficient stack for the LLL/controller thread or memory pressure, corrupting the prepare state.

You can narrow it down by decoding the fault with the addr2line against your .elf output file, or look at what runs just before the application asserts.

Can you also share what NCS version you're using and what Bluetooth controller you're using (Zephyr or the Nordic SoftDevice controller).

Best regards,

Simon

RE: hci uart sample asserts

Ypenburg — Wed, 22 Jul 2026 10:21:46 GMT

Hi,

What do you mean? I use both extra.conf and prj.conf to configure the hci uart sample. The extra configs are required for the ble features we use.

Br,

Renger

RE: hci uart sample asserts

Kazi Afroza Sultana — Mon, 20 Jul 2026 14:49:58 GMT

Hello Renger,

Can you please tell how have you used the configuration from extra.conf file?

RE: hci uart sample asserts

Ypenburg — Thu, 16 Jul 2026 13:41:32 GMT

Hi,

You don't get an error while compiling.

When you run the build and let the host scan for advertising devices and connect to these devices, the error will occur randomly after reading data (from whatever characteristic). I have to wait for about 6m on average when the host continuously connects, reads, disconnects.

You have to use the long range phy for scanning, advertising and connecting.

Thanks,

Renger

RE: hci uart sample asserts

Kazi Afroza Sultana — Thu, 16 Jul 2026 10:12:00 GMT

Hello,

I have added the configurations from the prj.conf file from your 3808.prj.con in the hci_uart application. NCS version 3.1.1. There was no errror in the build.

How have you used this ectra.conf file? Which NCS version you are using?

Thanks.

BR
Kazi

RE: hci uart sample asserts

Ypenburg — Thu, 09 Jul 2026 20:44:11 GMT

devzone.nordicsemi.com/.../3808.prj.conf devzone.nordicsemi.com/.../extra.conf

I don't know what part of the code leads to the assert.

I just use the hci uart sample with some specific settings (long range phy) set as we use that in our products.

Except for the config files and the overlay, the project is identical to the hci uart sample

What I do is connect to target boards via the long range phy. Reading data from characteristics leads to the error.

RE: hci uart sample asserts

Kazi Afroza Sultana — Mon, 06 Jul 2026 09:21:05 GMT

Hello,

Is this nordic board or your custom board?

Could you please share the prj.conf file and some part of the code which leads to the assert?

Thanks.

Kazi