Datasheet

NXP Semiconductors

UM11121

LPCXpresso51U68

UM11121

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User manual

Rev 1.1 — 27 April 27, 2018

15 of 22

Debugging LPC51U68 target using on-board (Link2) debug probe

To use the on-board Link debug probe, the LPCXpresso51U68 board must be powered

from the Link2 USB connector J6, and jumper JP2 must be fitted in position pin 1 - 2

(Local Target). Jumper JP1 must be open to enable the target LPC51U68. Connecting

the micro USB J6 to a host computer will power the Link and Target sections of the board

and provide the USB link to the debug tool software.

Debug LPC51U68 target using external debug probe

To use an external debug probe, connect the probe to the SWD (P1) connector, power

the LPC51U68 Target section of the board from the Target micro USB connector J5, and

fit a jumper to JP2 across pin 1 - 2 (Local Target). Jumper JP1 must be open to enable

the target LPC51U68. The on-board Link2 debug probe must be unpowered, by leaving

J7 unconnected.

On-board Link2 flash programing

To program the Link2 onboard flash memory, the Link2 MCU must be in DFU mode. If

the Link2 already has a valid image in the flash (as it normally will after coming from the

factory), you will need to force it into DFU mode by placing a jumper shunt on JP7, then

power the board by connecting the micro USB J6 to a host computer. Link2 MCU

programming is performed using the LPCScrypt utility (see

http://www.nxp.com/lpcutilities). Instructions for using the tool are located at the same

web page.

6.2 Using on-board Link2 to debug an off-board target LPC MCU

The LPCXpresso51U68 board’s Link2 debug probe may be used to debug an off-board

target MCU. The on-board Link2 debug probe is capable of debugging target MCU’s

with a VDDIO range of 1.6V to 3.6V. To keep the on-board target LPC51U68 MCU from

interfering with the SWD interface, JP1 must be fitted. The Link2 debug probe SWD is

connected by a ribbon cable between the P1 connector to the off-board target MCU SWD

interface. Power the LPCXpresso51U68 board from the Link USB connector J6, and fit

jumper JP2 across pins 2 - 3 (External Target).