Configuring the Microbit v2.21 for AoD

Hello, i've got two of the Microbit V2.21 with the N52833 chips.

I'm attempting to use these microbits with the AoA antenna.

However when i Flash the direction_finding_peripheral example to the microbit, i get these errors:

*** Booting nRF Connect SDK v2.5.0 ***
[00:00:17.186,157] <inf> bt_sdc_hci_driver: hci_driver_open: SoftDevice Controller build revision:
                                            c5 93 ba a9 14 4d 8d 05  30 4e 9b 92 d7 71 1e e8 |.....M.. 0N...q..
                                            aa 02 50 3c                                      |..P<             
[00:00:17.188,323] <inf> bt_hci_core: hci_vs_init: HW Platform: Nordic Semiconductor (0x0002)
[00:00:17.188,354] <inf> bt_hci_core: hci_vs_init: HW Variant: nRF52x (0x0002)
[00:00:17.188,385] <inf> bt_hci_core: hci_vs_init: Firmware: Standard Bluetooth controller (0x00) Version 197.47763 Build 2370639017
[00:00:17.189,239] <inf> bt_hci_core: bt_dev_show_info: Identity: DF:72:6D:43:54:6E (random)
[00:00:17.189,300] <inf> bt_hci_core: bt_dev_show_info: HCI: version 5.4 (0x0d) revision 0x1102, manufacturer 0x0059
[00:00:17.189,331] <inf> bt_hci_core: bt_dev_show_info: LMP: version 5.4 (0x0d) subver 0x1102
Bluetooth initialized
Advertising successfully started
Set CTE transmission params...[00:00:18.652,099] <err> mpsl_init: m_assert_handler: MPSL ASSERT: 112, 2136
[00:00:20.620,452] <err> os: hard_fault: ***** HARD FAULT *****
[00:00:20.620,452] <err> os: hard_fault:   Fault escalation (see below)
[00:00:20.620,483] <err> os: hard_fault: ARCH_EXCEPT with reason 3

[00:00:20.620,483] <err> os: esf_dump: r0/a1:  0x00000003  r1/a2:  0x00000000  r2/a3:  0x00000003
[00:00:20.620,513] <err> os: esf_dump: r3/a4:  0x20001480 r12/ip:  0x0008ba06 r14/lr:  0x00011fb9
[00:00:20.620,513] <err> os: esf_dump:  xpsr:  0x41000018
[00:00:20.620,544] <err> os: esf_dump: Faulting instruction address (r15/pc): 0x0001d784
[00:00:20.620,605] <err> os: z_fatal_error: >>> ZEPHYR FATAL ERROR 3: Kernel oops on CPU 0
[00:00:20.620,605] <err> os: z_fatal_error: Fault during interrupt handling

[00:00:20.620,635] <err> os: z_fatal_error: Current thread: 0x20001a48 (unknown)
[00:00:20.712,310] <err> fatal_error: k_sys_fatal_error_handler: Resetting system

I'm attempt to connect to one of the AoA antennas, please ask if you need more information, i'm new to this whole bluetooth microcontroller world.
The error above is from gdb however without it looks like this:
<wrn> bt_hci_core: bt_hci_cmd_send_sync: opcode 0x2055 status 0x01

Likewise when i debug the module itself, i get these parameters:

Likewise the antenna i'm attempting to connect to is a NRF52833 sdk board, with the AoA antenna attached, and the direction finding central example.

  • With this configuration:

    # Copyright (c) 2022 Nordic Semiconductor ASA
    # SPDX-License-Identifier: Apache-2.0



    # Enable Direction Finding Feature RX in connected mode

  • Hi,

    I am afraid I am struggling a bit in understanding your setup.

    You mention a micro:bit, an nRF52833 DK and an antenna array, which all are somehow connected. Is this by physical connections (wires,) and if so what pins/headers/etc. are connected to what?

    Please note that there is no way to physically (by wires) connect "through" the nRF52833 DK, from a different board, to an antenna array in the other end. The normal way would be to use a direction finder sample on the nRF52833 DK with the antenna array connected (the side of direction finding requiring an antenna array), and then have the corresponding direction finding sample on the other device (the side of the direction finding using only one antenna.) Those two direction finding samples are different.

    With your current setup:

    • What sample is put on what device (where by device I mean e.g. micro:bit, nRF52833 DK, etc.)?
    • What device has the antenna array, and what are the physical connections?
    • What antenna array are you using?


  •  Hej Terje, sorry for the confusion, let me see if i cant make it a bit clearer.
    I have a PCA20054 direction finding atenna with a nrf52833dk_nrf52833, the PCA20054 and dk is running the "direction finding central" from NRF, this part seems to work fine.

    Secondly i have a microbit V2.21, on the Microbit, i'm trying to run the "direction finding perphial" example, in the configuration of the example, i have disabled the direction finding antenna.

    The "direction finding perphial" comes as far as establishing the bluetooth connection, however when i try and configure the CTE response, on the Microbit, i get the error from above, all the configuration and screenshots from above relates to the Microbit.

    The problem mostly is that when the Microbit tries to configure a CTE response by calling bt_df_set_conn_cte_tx_param function, the Microbit hard crashes.

  • Hi,

    Thank you for the clarifications. Your setup looks right.

    I assume that you followed the instructions, and built the project in AoA mode (basically set OVERLAY_CONFIG to the overlay-aoa.conf file, as per the Bluetooth: Direction finding peripheral documentation)?

    I also assume that you configured the sample for the bbc_microbit_v2 board?

    Can you clarify what you do to "configure the CTE response"? Are you simply referring to building and running the (unmodified) sample, and it fails at that point in code?

    I do not have a BBC Micro:Bit v2 right now, but I will try to get hold of one to reproduce. In the mean time, answers to the above questions would be great.


  • Hi,

    For CTE RX you must use the Zephyr Controller, not the SoftDevice Controller. For the Zephyr Controller you must use nRF Connect SDK v2.1, and not v2.5 as you use here.