This project provides a Python-based GUI to display, filter and highlight real-time ARM Cortex microcontroller log messages received via SEGGER's Real-Time Transfer (RTT) debug protocol.
This debug protocol provides direct communication with ARM Cortex-based microcontrollers via J-Link debug probes. RTT removes the need for additional debug channels during development (like UART) by using the ARM Cortex SWD/JTAG interface. Unlike the slower and clunkier UART debug channel the SWD, JTAG interface provides lean and mean RTT debug messages for ARM MCUs.
This project interfaces directly with the J-Link debug probe drivers,
using the Python library pylink which wraps the JLink drivers to interact with a J-Link debug probe.
It does NOT require any other intermediary software like Segger's RTT Viewer.
The pylink library was written by Square Inc. (Now Block Inc.), open sourced https://github.com/square/pylink and uploaded to PyPI https://pypi.org/project/PyLink/.
The official documentation and examples for the pylink library
are somewhat lacking when it comes to using the RTT channel,
so this project may also serve as a practical guide for leveraging pylink for RTT communication.
Since messages are processed directly in Python, it should be straightforward, to extend the functionality of this GUI with other new debug features like data plotting and analysis - capabilities that are not yet available in SEGGER's RTT applications.
- Direct J-Link connection using native drivers (no RTTViewer required)
- Real-time display of debug communication
- Log filtering and message highlighting
- Broad MCU support through intuitive selection interface
- Connection status monitoring and management
- Extensible architecture for custom processing (plotting, analysis, etc.)
- Python 3.8+ (https://www.python.org/)
- SEGGER J-Link Software (Download)
- Required Python packages (Defined in requirements.txt file):
- FreeSimpleGUI
- pylink (Python wrapper for J-Link drivers)
Include the SEGGER RTT library files in your embedded app. See: https://www.segger.com/products/debug-probes/j-link/technology/about-real-time-transfer/
Include RTT in your firmware by using the source code from JLink/Samples/RTT included in J-Link installation.
#include "SEGGER_RTT.h"
void main() {
SEGGER_RTT_Init();
SEGGER_RTT_SetTerminal(0);
SEGGER_RTT_printf(0, "System started\n");
}- The fastest way is to download and run the GUI executable
- Download matching executable (windows or linux) from the releases page:
https://github.com/SaturnIC/RTT-ARM-Cortex-GUI/releases
- Run the executable
- Clone the repository:
https://github.com/SaturnIC/RTT-ARM-Cortex-GUI.git cd RTT-ARM-Cortex-GUI - Install the required packages:
pip install -r requirements.txt # or explicitly pip install FreeSimpleGUI==5.0.0 pylink - Ensure that the J-Link drivers are installed and accessible on your system.
- Launch the application:
python rtt_python_gui.py
-
Select your target MCU from the dropdown list. Filter MCU list by typing a matching substring in the MCU dropdown widget.
-
Click "Connect" to establish a connection.
Enter text in highlight box to highlight matching messages
Filter log messages by entering a filter substring in the filter box
Use the "Disconnect" button to terminate the connection.
Use the "Clear" button to reset the log display.
This project is licensed under the Apache License, Version 2.0. See LICENSE for more details.
For questions, issues, or contributions, please contact the maintainer
Note: Requires properly installed J-Link drivers. The application communicates directly with debug hardware using SEGGER's pylink Python wrapper.