nRF52833 custom board Hard Fault when using Bluetooth

[Kesims]

Hello,

I am trying to get into Zephyr development and for my project I have created a custom board based on nRF52833 QDAA (40 pin). I have been successfully able to verify the board functionality using the nRF5 SDK by using some of the examples provided by Nordic.

Unfortunately I am running into issues when trying to use nRF Connect SDK (version 2.5.0).

The board seems to work pretty well, but when I enable Bluetooth (for example just a simple advertising), the board successfully starts up, sends out one advertisement packet and then crashes.

[00:00:00.017,547] <err> mpsl_init: MPSL ASSERT: 112, 2185
[00:00:00.017,578] <err> os: ***** HARD FAULT *****
[00:00:00.017,578] <err> os:   Fault escalation (see below)
[00:00:00.017,608] <err> os: ARCH_EXCEPT with reason 3

[00:00:00.017,608] <err> os: r0/a1:  0x00000003  r1/a2:  0x00000000  r2/a3:  0x00000009
[00:00:00.017,639] <err> os: r3/a4:  0x20001090 r12/ip:  0x20000970 r14/lr:  0x0000bbe5
[00:00:00.017,639] <err> os:  xpsr:  0x41000018
[00:00:00.017,669] <err> os: Faulting instruction address (r15/pc): 0x000108b8
[00:00:00.017,700] <err> os: >>> ZEPHYR FATAL ERROR 3: Kernel oops on CPU 0
[00:00:00.017,730] <err> os: Fault during interrupt handling

[00:00:00.017,761] <err> os: Current thread: 0x20001090 (logging)
[00:00:00.478,393] <err> os: Halting system

From the zephyr.map I have found out that the faulting instruction is part of zephyr/arch/arch/arm/core/aarch32/libarch__arm__core__aarch32.a(irq_manage.c.obj).

I am stuck at this issue as I have no idea what could be the cause or how to resolve it, when I build the firmware for nRF52833DK and flash it on the DK, it seems to be running fine.

My prj.conf:

# Bluetooth configuration
CONFIG_BT=y
CONFIG_BT_DEVICE_NAME="BugPack"

# Logging configuration
CONFIG_LOG=y

To be honest, I have no idea what to do about this, how to debug the issue, as I have just started working with Zephyr. Any help with the issue would be very appreciated.

I will also attach the board schematic and Zephyr board files.

Thank you very much in advance!

Matej


bugpack.zipSchematic_BugPack_v2.pdf

[Vidar Berg]

Hello Matej,

Please try to measure the startup time of your 32M crystal as I suggested in this post:  RE: MPSL ASSERT: 112, 2134 if using multiple BLE communication . The MPSL assertion indicates that the crystal oscillator was not active when it was supposed to.

Best regards,

Vidar 

[Kesims]

First of all, thank you very much for your response.

It seems like the crystal is not starting at all? The code gets stuck in the while loop. I have tried replacing the crystal as well as capacitors, but no luck so far.

I am using the following crystal, I suppose that should be alright? https://www.lcsc.com/product-detail/Crystals_HD-7E032000F01_C655046.html Originally I have tried starting it up with 8pF capacitors, later with 12pF capacitors, without any success.

I have also figured out that I can start the device and run BT on it when I enable CONFIG_BT_LL_SW_SPLIT=y  in the prj.conf

Do you by any chance have any other ideas? I might as well try to assemble one more prototype board just to make sure it is not some weird hardware issue caused by repeated re-soldering of some components on the current board...

UPDATE: The issue is unfortunately present on both prototypes. Unfortunately don`t have an oscilloscope at home to check what is going on... I will have an access to one during the week though.

[Vidar Berg]

Kesims said:

I have also figured out that I can start the device and run BT on it when I enable CONFIG_BT_LL_SW_SPLIT=y  in the prj.conf

Are you able to discover and establish a Bluetooth connection with your board? 

[Kesims]

Yes, the Buetooth communication works fine when this option is enabled.

[Vidar Berg]

Thanks for confirming. This suggests that the crystal is working correctly. If it was giving the wrong frequency, you would not be able to see the advertisements or connect to the device. Before starting the crystal, please check if the XTAL bit is set in HFCLKSTAT.