Table 25. Supported debug scenarios (continued)
Debug scenario
Feature support
— MCU-Link SWD feature is enabled (MCU-Link SWD disable jumper
JP27 is open)
— Connect the external target MCU to the target MCU SWD connector J38
• VCOM: MCU-Link VCOM feature is not supported
• USBSIO: MCU-Link USBSIO feature is not supported
• Target selection: Short target selection jumper JP7
• Target power selection:
— If the external target MCU has to get power from the board, then set
target power selection jumper JP8 to 1-2 shorted
— If the external target MCU has to use its own power, then set jumper JP8
to 2-3 shorted
3.5 Connecting to a target through a USB-to-UART bridge
MCU-Link supports the VCOM serial port feature, which adds a serial COM port on the host computer, and connects it to the target
MCU by using MCU-Link as a USB-to-UART bridge.
In the LPC55S36-EVK board, MCU-Link is connected to the Flexcomm 0 (USART) port of the target MCU through a voltage
translator U22, which enables communication between MCU-Link and the target MCU, by shifting voltage levels of signals
between the two devices from 3.3 V to 3.3/1.9 V and vice versa.
To use MCU-Link as a USB-to-UART bridge, verify the following jumper settings and connect the J1 connector on the board to
the USB port of the host computer:
• Jumper JP25 is open (MCU-Link is in Normal mode)
• Jumper JP26 is open (USB-to-UART bridge is enabled)
When you boot the LPC55S36-EVK board, a VCOM port with the name MCU-Link Vcom Port (COMxx) is enumerated on the
host computer, where “xx” may vary from one computer to another. Each MCU-Link based board has a unique VCOM number
associated with it.
The USB-to-UART bridge (VCOM feature) can be disabled so that the target MCU USART port can be used for other purposes.
For example, to create an external UART connection from USART connecter JP3 using a USB-to-serial cable.
The USB-to-UART bridge can be disabled by disabling voltage translator U22 (setting it to high impedance). To disable U22,
unpower the LPC55S36-EVK board and short jumper JP26. Shorting/opening JP26 after powering up the board has no impact on
the functions/features of the MCU-Link firmware. When VCOM feature is disabled, then the target MCU UART port can be used
for other purposes.
3.6 Connecting to a target through a USB-to-SPI or USB-to-I2C bridge
MCU-Link supports the USB serial input/output (USBSIO) port feature, which adds a USB serial I/O port on the host computer, and
connects it to the target MCU by using MCU-Link as a USB-to-SPI bridge or USB-to-I2C bridge. Support for the USBSIO feature
can be enabled on the host computer using the libusbsio library, which is a free host library from NXP for Windows/Linux/MacOS
systems. For more details on the libusbsio library, see
.
In the LPC55S36-EVK board, MCU-Link is connected to the Flexcomm 8 (HS SPI) port of the target MCU using slave select 1
connection, through a voltage translator U24, which enables communication between MCU-Link and the target MCU, by shifting
voltage levels of signals between the two devices from 3.3 V to 3.3/1.9 V and vice versa.
NXP Semiconductors
MCU-Link Debug Probe
LPC55S36-EVK Board User Manual, Rev. 1, 24 January 2022
User Manual
45 / 49