Unable to flash custom board[NRF54L05] using NRF54L15 DK

[NithinAG]

Hi,

I am working on a custom board which is NRF54L05 connected to NRF54l15 DK via P19

NRF54l15 DK version: PCA10156 0.9.3

Serial wire debug cable length: 15cms

Breakout board to custom board:

SWIO -> SWDIO

CLK -> SWDCLK

Vref -> VDD

GND -> GND

here is an image:

Whenver I try to flash with the custom board connected, the DK board gets flashed. So, it looks like the custom board isnt recognized at all. The code seems to be fine as I can control button and led on the DK board. 

Am I missing something? Is there a way to connect the custom board directly to the p0, p1 or p2 slots on the DK via jumpers?

Thanks in Advance,

Nithin

[SwRa]

Hi Nithin,

The following are the connections that needeed:

• Pin 1: SWD0_VTG → target VDD (or used to power the target)
• Pin 2: SWD0_SWDIO → target SWDIO
• Pin 3: SWD0_SELECT → must be tied to GND on the external board
• Pin 4: SWD0_SWDCLK → target SWDCLK
• Pin 5: GND → target GND
• Pin 10: SWD0_RESET → target RESET (optional but recommended)

Refer: https://docs.nordicsemi.com/bundle/ug_nrf54l15_dk/page/UG/nRF54L15_DK/program_debug/debug_out_ext_board.html 

It seems that you have missed out the SWD0_SELECT. If SWD0_SELECT is left floating or high, the onboard debugger will keep talking to the DK’s own nRF54L15 instead of your external nRF54L05.

Also, for the nRF54L15 DK there is a known issue with the level shifters: It is recommended to use cables no longer than ~8–10 cm since longer cables can cause the external target not to be detected or give J‑Link errors. See this ticket:  nRF54L DK can't program external MCU via SWD – J-Link error (Unknown Error in DLL)  

Best Regards,

Swathy

[NithinAG]

Hi, 

Thanks for the info. Looks like i have got the board up and running.

But, when i try to flash I get this error:

Device error: Setting the debug port SELECT register failed while powering up sys and debug regions (Unknown Error in J-Link DLL (error code =-1)).

Simliar to the error described in the theard you have linked for the length of the wire. Is this due to the wire length? ot is this something else?

Haven been unable to find a shorternwire here. I'll try to find one and try.