nRF54L DK - ESB Sample LF Clock Source Configuration Issue

[Doris.chen]

Hello,

I am currently using the nRF54L DK and running the ESB (Enhanced ShockBurst) sample in nRF Connect SDK v2.8.0. I would like to change the LF (low-frequency) clock source from XTAL to RC (LFRC), so I added the following configurations in prj.conf:

CONFIG_CLOCK_CONTROL_NRF_K32SRC_RC=y
CONFIG_CLOCK_CONTROL_NRF_K32SRC_500PPM=y

The build process completes successfully, but after flashing the firmware, the device continuously resets and encounters the following error:

*** Booting nRF Connect SDK v2.8.0-a2386bfc8401 ***
*** Using Zephyr OS v3.7.99-0bc3393fb112 ***
I: Enhanced ShockBurst ptx sample
I: GPIO_Init
D: HF clock started
I: Initialization complete
I: Sending test packet
I: Allocated GRTC channel 6

ASSERTION FAIL @ WEST_TOPDIR/zephyr/drivers/clock_control/clock_control_nrf.c:626
E: r0/a1:  0x00000004  r1/a2:  0x00000272  r2/a3:  0x00000000
E: r3/a4:  0x00000004 r12/ip:  0x00000000 r14/lr:  0x0004a4fd
E:  xpsr:  0x2100011e
E: Faulting instruction address (r15/pc): 0x00050eca
E: >>> ZEPHYR FATAL ERROR 4: Kernel panic on CPU 0
E: Fault during interrupt handling

E: Current thread: 0x20013768 (unknown)
*** Booting nRF Connect SDK v2.8.0-a2386bfc8401 ***
*** Using Zephyr OS v3.7.99-0bc3393fb112 ***
I: Enhanced ShockBurst ptx sample
I: GPIO_Init
D: HF clock started
I: Initialization complete
I: Sending test packet
I: Allocated GRTC channel 6

ASSERTION FAIL @ WEST_TOPDIR/zephyr/drivers/clock_control/clock_control_nrf.c:626
E: r0/a1:  0x00000004  r1/a2:  0x00000272  r2/a3:  0x00000000
E: r3/a4:  0x00000004 r12/ip:  0x00000000 r14/lr:  0x0004a4fd
E:  xpsr:  0x2100011e
E: Faulting instruction address (r15/pc): 0x00050eca
E: >>> ZEPHYR FATAL ERROR 4: Kernel panic on CPU 0
E: Fault during interrupt handling

E: Current thread: 0x20013768 (unknown)
*** Booting nRF Connect SDK v2.8.0-a2386bfc8401 ***
*** Using Zephyr OS v3.7.99-0bc3393fb112 ***
I: Enhanced ShockBurst ptx sample
I: GPIO_Init
D: HF clock started
I: Initialization complete
I: Sending test packet
I: Allocated GRTC channel 6

ASSERTION FAIL @ WEST_TOPDIR/zephyr/drivers/clock_control/clock_control_nrf.c:626
E: r0/a1:  0x00000004  r1/a2:  0x00000272  r2/a3:  0x00000000
E: r3/a4:  0x00000004 r12/ip:  0x00000000 r14/lr:  0x0004a4fd
E:  xpsr:  0x2100011e
E: Faulting instruction address (r15/pc): 0x00050eca
E: >>> ZEPHYR FATAL ERROR 4: Kernel panic on CPU 0
E: Fault during interrupt handling

E: Current thread: 0x20013768 (unknown)
*** Booting nRF Connect SDK v2.8.0-a2386bfc8401 ***
*** Using Zephyr OS v3.7.99-0bc3393fb112 ***
I: Enhanced ShockBurst ptx sample
I: GPIO_Init
D: HF clock started
I: Initialization complete
I: Sending test packet
I: Allocated GRTC channel 6

ASSERTION FAIL @ WEST_TOPDIR/zephyr/drivers/clock_control/clock_control_nrf.c:626
E: r0/a1:  0x00000004  r1/a2:  0x00000272  r2/a3:  0x00000000
E: r3/a4:  0x00000004 r12/ip:  0x00000000 r14/lr:  0x0004a4fd
E:  xpsr:  0x2100011e
E: Faulting instruction address (r15/pc): 0x00050eca
E: >>> ZEPHYR FATAL ERROR 4: Kernel panic on CPU 0
E: Fault during interrupt handling

E: Current thread: 0x20013768 (unknown)
*** Booting nRF Connect SDK v2.8.0-a2386bfc8401 ***
*** Using Zephyr OS v3.7.99-0bc3393fb112 ***
I: Enhanced ShockBurst ptx sample
I: GPIO_Init
D: HF clock started
I: Initialization complete
I: Sending test packet
I: Allocated GRTC channel 6

Could you advise on the correct way to enable LFRC on the nRF54L?

• Are there additional CONFIG_CLOCK_CONTROL_NRF_K32SRC_* parameters required?
• Are there any known limitations or additional initialization steps needed?

I appreciate your support!

Best Regards,
Doris