Sometimes I have a wish. Not every time it gets fulfilled. But this time I’m lucky and happy developer. A few days ago I wrote about the LPC4322-based SEGGER OB (on-board) J-Link firmware. It works great, but the board requires another USB cable to power the target board.

Rolf Segger contacted me, and a few days later I had a J-Link firmware with a ‘power-on’ feature:

That way, only one USB cable is needed. All what you need to do is to update the firmware.

Go to https://www.segger.com/downloads/jlink/#LPC-Link2 and download the ‘NXP LPC-Link2 On-Board’ firmware file.

Copy that file into the LPCXpressoV2 folder:

Next, set the boot mode jumper and power the board:

Then run the program_JLINK script:

Verify that the correct image file is used:

Remove the boot jumper and power the board again:

Debug Configuration

The final piece is to tell the J-Link firmware to turn on the power. For this have the ‘Power Target’ option enabled in the launch configuration:

This passes the following startup parameter to the J-Link GDB server for 5V (value is ignored for this board):

-powertarget 50

Alternatively, the J-Link Commander can be used with

power on

or with with the command string

exec SupplyPower = <1|0>

With this, I only need a single USB cable, and I can manually turn on/off the target device too, which is an extra benefit. Thanks Rolf!

Happy wishing:-)

Links

• Upgrading LPC4322-based Debug Probe Firmware on RT10xx
• SEGGER download page: https://www.segger.com/downloads/jlink/#LPC-Link2