UM11158
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© NXP B.V. 2022. All rights reserved.
User manual
Rev. 1.6 — 17 March 2022
12 of 24
NXP Semiconductors
UM11158
LPCXpresso55S69/55S28 Development Boards
4. On-board (Link2) Debug probe
This section describes the features provided by the on-board Link2 Debug Probe,
including how to use this to debug an exernal target.
The Link2 Debug Probe is implemented using an LPC432x MCU (circuit reference U2),
which provides a high speed USB port interface to the host computer that runs the
development tools. This device is not intended for developer use, and should only be used
with approved firmware images from NXP. The Link2 on-chip flash memory is factory
programmed with a firmware image that supports CMSIS-DAP debug protocol, but also
includes other USB end point functions:
•
Virtual COM (VCOM) port: a serial device that can be used with any host computer
application design for serial port communication (e.g. Teraterm, puTTY, etc.) Set the
terminal program for baud rate to 115200, no parity, 8 bit data, 1 stop bit, no flow
control.
•
SWO trace end point: this virtual device is used by MCUXpresso to retrieve SWO
trace data. See the MCUXpresso IDE documentation for more information.
•
I2S/SPI bridges: bridge device from I2C and SPI ports of the LPC target.
All of these devices are independent of each other and of the CMSIS-DAP debug device
that is enumerated when the board is connected to a host computer; for example, the
VCOM port can be used if the board is running an application when no debugger is
running.
In order to correctly install and use the Link2 device on the LPCXpresso55S69 (required
for any debugging purpose) for Windows 7 or 8 host computers, install the drivers first.
These drivers will automatically be installed when MCUXpresso IDE has already been
installed. If these IDEs are not being used, it is recommended LPCScrypt be installed as
this also includes the required drivers. All these tools and utilities are available for free
download at https://www.nxp.com/lpcscrypt.
The CMSIS-DAP firmware image installed at the factory (and by LPCScrypt) will uniquely
identify itself to the host computer so that more than one board can be connected to that
host computer at any time. Some toolchains cannot discern between multiple debug
devices; refer to your toolchain documentation for more information (note the
MCUXpresso IDE does support multiple LPCXpresso board targets.)
Note: The Link2 only boots when the board is power cycled; the reset button on the board
does not reset the Link2.
When using MCUXpresso IDE, the Link2 can be automatically booted with the latest /
most appropriate firmware for that IDE version by installing J4 (DFU jumper) before
powering up the board. This is the recommended approach for the MCUXpresso IDE.
Note that if J4 is installed when powering the board then the VCOM port (and other
devices mentioned above) device will not appear until the MCUXpresso IDE boots the
Debug Probe. The Debug Probe is booted once a debug session is started (that is, the
IDE attempts to download code to the target).
