We are unable to connect the nRF54L15 DK Debug Out port to our external nRF54L15 pre-production board. Error: code: 1, description: Generic, message: Batch task protection-get failed, Device error: Setting the debug port SELECT register failed

[Steve]

We have the Nordic nRF54L15-DK PCA10156 0.9.3 2025.19

We use nRF Connect for Desktop v5.2.1 and Programmer v4.7.2 and connect by USB to our ASI_nRF54L_DK1 001057739416.

Windows OS: Windows 11 Pro v 25H2 build 26200.7623

PC Hardware: Intel Core i7-8700 3.2GHz  16GB RAM  64-bit OS, x64 processor

The Programmer Logs the following initialization:

14:19:58.371

Initialising the bundled nrfutil device

14:19:59.280

Using the bundled core version for nrfutil device: 8.1.1

14:19:59.307

Using nrfutil device version: 2.15.7

14:19:59.308

Using nrf-device-lib version: 0.22.5

14:19:59.308

Using nrf-probe version: 0.51.0

14:19:59.308

Using SEGGER J-Link version: JLink_V8.76

14:19:59.325

Getting serial port options from the persistent store for AH02X0KT.pc-nrfconnect-programmer

14:19:59.326

Device connected with the serial number AH02X0KT

14:21:06.589

Getting serial port options from the persistent store for 001057739416.pc-nrfconnect-programmer

14:21:06.589

Device connected with the serial number 001057739416

14:21:06.613

Getting serial port options from the persistent store for 001057739416.pc-nrfconnect-programmer

The setup works fine for programming the DK's BLE chip.

We are following the instructions from the nRF54L15_DK_HW__USER_Guide_v0.9.1.pdf for programming an external board, but always get this error:

12:33:34.446 Failed "reading readback protection status for application core". Error: code: 1, description: Generic, message: Batch task protection-get failed, Device error: Setting the debug port SELECT register failed while powering up sys and debug regions (Unknown error in the J-Link DLL (error code =-1)). This might indicate that the debug port is unavailable. Double-check device power supply and SWD lines, and ensure that SWD is not disabled
12:33:58.273

These are our Connections from P19 DEBUG_OUT to our external board:

• Power Supply 2.5V to SWDO_VTG and to our board's BLE VDD.
• GND to Ground
• SWDO_SWDIO to SWDIO
• SWDO_SELECT to Ground
• SWDO_SWDCLK to SWDCLK
• SWD0_SW0  Not Used
• SWDO_RESET  Not Used

Is the RESET connection required now? Because on nRF52 devices, Reset would break the programming. What must we do to enable the SWD? What J-LINK Settings should we use on the Programmer GUI?

[Ressa]

Hi Steve,

The RESET pin is not required but you must make sure it is stable during programming. The connections you have between DK and your custom board is fine. Also since you can program DK BLE SoC then it means the issue is mainly from hardware not software settings or version. One common issue when using DK for programming external boards is having long wires which gives exactly similar behavior. So based on that may I know the lengths of the wires used for connections?  Please make sure the wires for connecting external board to DK is as short as possible (less than 10 cm). 

[Steve]

Thanks Ressa, these are helpful hints, but we are using a probe station to connect the external board - the programming signals need to go through manual manipulators and can only be shortened so much. Is it possible to reduce the comm rate for this situation?

[PaKa]

No, this is a physical limitation with the drivers on the DK. For longer cables you will probably need to use a dedicated debugger with different driver stage for the lines.

[Ressa]

Hi Steve, 

As Paal mentioned, the standard approach in your scenario would be to have some sort of driver/buffer for the lines or to use different debugger than DK debug out port. Also if the voltage on the boards are different, then having even shorter cable is recommended when using DK debug out port. 

Best regards,
Ressa

[Ressa]

Just as an experiment, you can try to paly with SWD clock speed using nrfjprog command. It is not a recommended approach but you can try to see if it makes any difference: