SLAU969 December   2025

 

  1.   1
  2.   Description
  3.   Get Started
  4.   Features
  5.   Applications
  6.   6
  7. 1Evaluation Module Overview
    1. 1.1 Introduction
    2. 1.2 Kit Contents
    3. 1.3 Specification
    4. 1.4 Device Information
  8. 2Hardware
    1. 2.1 Hardware Overview
    2. 2.2 Power Requirements
    3. 2.3 XDS110 Debug Probe
    4. 2.4 Measure Current Draw of the MSPM33C321A
    5. 2.5 Clocking
    6. 2.6 BoosterPack Plug-in Module Pinout
    7. 2.7 Mikrobus Module Pinout
    8. 2.8 External Storage
    9. 2.9 OLED Display Module
  9. 3Software
    1. 3.1 Software Development Options
    2. 3.2 Out-of-Box
    3. 3.3 CCS Cloud
  10. 4Hardware Design Files
    1. 4.1 Schematics
    2. 4.2 PCB Layouts
    3. 4.3 Bill of Materials (BOM)
  11. 5Compliance Information
    1. 5.1 Compliance and Certifications
  12. 6Additional Information
    1. 6.1 Trademarks
  13. 7Related Documentation
    1. 7.1 Supplemental Content
  14. 8Revision History

2.3 XDS110 Debug Probe

LP-MSPM33C321A features an onboard debug probe to streamline prototyping. The debugger used on this LaunchPad is the XDS110 variant, which supports all MSPM33 device derivatives. The integrated XDS110 debug probe is separated from the rest of the MSPM33C321A circuitry, which is shown by the dashed silkscreen on the LaunchPad. The XDS110 is only connected through signals that pass through J101, in addition to a common ground.

Isolation Jumper Block

The isolation jumper block J101 allows the user to connect or disconnect signals that cross from the XDS110 domain into the MSPM33C321A target domain. This includes XDS110 SWD signals, application UART signals, 3.3V and 5V power, reset, and a VBAT source.

Table 2-2 Isolation Jumper Block
JumperDescription
5V5V rail from the USB
3V33.3V rail from the LDO
RXD<<Backchannel UART: The target MSPM33C321A receives data through this signal. The arrows indicate the direction of the signal.
TXD>>Backchannel UART: The target MSPM33C321A sends data through this signal. The arrows indicate the direction of the signal.
NRST Reset signal
SWDIOSerial Wire Debug: SWDIO data signal
SWCLKSerial wire debug: SWCLK clock signal
BSLInvoke pin for bootstrap loader. Allows the XDS110 to invoke BSL.
BAT VBAT selection between the LDO on the XDS110 side and 100mF super capacitor.

During normal prototyping all shunts are populated. However, there are some scenarios where a user needs to open these connections:

  • To remove any and all influence from the XDS110 debug probe for high accuracy target power measurements.
  • To control 3.3V and 5V power flow between the XDS110 and target domains.
  • To expose the target MCU pins for other use than onboard debugging and application UART communication.
  • To expose the programming and UART interface for the XDS110 so that the XDS110 can be used for devices other than the onboard MCU.
  • To utilize other VBAT options.

Application (Backchannel) UART

The backchannel UART allows communication with the USB host that is not part of the target application’s main functionality. This is very useful during development, and also provides a communication channel to the PC host side. This can be used to create graphical user interfaces (GUIs) and other programs on the PC that communicate with the LaunchPad development kit.

On the host side, a virtual COM port for the application backchannel UART is generated when the LaunchPad development kit enumerates on the host. You can use any PC application that interfaces with COM ports, including terminal applications like HyperTerminal or Docklight, to open this port and communicate with the target application. You need to identify the COM port for the backchannel. On Windows PCs, Device Manager can assist.

LP-MSPM33C321A Application Backchannel UART in Device Manager Figure 2-3 Application Backchannel UART in Device Manager

The backchannel UART is the XDS110 Class Application/User UART port. In this case, Figure 2-3 shows COM14, but this port can vary from one host PC to the next. After identifying the correct COM port, configure the port in the host application according to documentation. The user can then open the port and begin communication from the host.

On the target MSPM33C321A side, the backchannel UART is connected to UART (PA10, PA11). The XDS110 has a configurable baud rate; therefore, the PC application configuring the baud rate needs to be the same baud rate.