One great thing with that new NXP LPC845-BRK board is that it is possible to use it with any standard SWD/JTAG debugger, as it has the 10pin debug header present on the board. It is not populated by default, because the LPC845-BRK includes a CMSIS-DAP debug probe already. But if I want to use a SEGGER J-Link, a P&E Multilink or the NXP LPCLink2, this is certainly something to consider:

To enable debugging the board with an external debug probe. I have to populate JP1 (Jumper) and CN3 (standard 10pin SWD header):

The jumper header and jumper is part of the kit content (see Unboxing the NXP LPC845-BRK Board), the SWD/JTAG header can be ordered from the usual stores, e.g. Samtec FTSH-105-01-L-DV-K from Digikey or from Mouser.

On the board there is the JP2 jumper which can be used if using an external debug probe:

JP2 is used to keep LPC11U325 CMSIS-DAP probe in Reset. If the debug probe is not used or under debug control, it seems to tristate the debug lines and does not affect the SWD debug lines. So using that jumper is not really needed unless I want to really silence the LPC11U35.

UPDATE: during this article I did not had the need somehow to have JP2 installed. But I really recommend having it installed with a jumper if using an external debug probe. Otherwise it could happen that you are not able to debug it.

The first step is to remove the solder which is on the pads for the SWD header as the solder mask for the board did not keep them out.

I’m using standard de-solder wick or braided copper for this:

Removing the solder from the pads:

I remove the solder because I want the header to be on the pads, not floating on the solder. Below the board with the solder removed:

Then put the header on the pads. I recommend to solder first one pad and with this align carefully the other pins. Then solder all pads.

With this I was able to debug the board with a SEGGER J-Link, P&E Multilink Universal or the NXP LPC-Link2 (below with a 3D printed custom enclosure):

Summary

The LPC845-BRK has an onboard CMSIS-DAP debug probe, so an external debug probe is not needed. But I love to have direct access to the CPU and freedom of choice for the debug probe I want to use. So adding that SWD gives me all the flexibility I need.

List of articles about the LPC845-BRK board:

• Unboxing the NXP LPC845-BRK Board
• Tutorial: Using external Debug Probes with NXP LPC845-BRK Board
• Tutorial: Transforming the NXP LPC845-BRK into a CMSIS-DAP Debug Probe
• Tutorial: Blinky with the NXP LPC845-BRK Board

Happy Soldering 🙂

Links

• Unboxing the NXP LPC845-BRK Board
• LPC845-BRK Board web page: https://www.nxp.com/LPC845Breakout
• User Guide for LPC845-BRK Board: https://www.nxp.com/docs/en/user-guide/UM11181.pdf
• NXP LPC845 web page: https://www.nxp.com/products/processors-and-microcontrollers/arm-based-processors-and-mcus/lpc-cortex-m-mcus/lpc800-series-cortex-m0-plus-mcus/low-cost-microcontrollers-mcus-based-on-arm-cortex-m0-plus-cores:LPC84X?
• MCUXpresso SDK: http://mcuxpresso.nxp.com/
• MCUXpresso IDE: New NXP MCUXpresso IDE V10.3.0 Release
• List of community projects: https://community.nxp.com/community/lpc/blog/2019/02/02/lpc845-brk-board-projects