Introduction
Whether you’re an experienced engineer or someone just beginning to explore embedded systems, this article series will help you get comfortable with NXP’s FreeMASTER tool. It’s written with both technical and non‑technical readers in mind, using simple explanations and practical examples to make the concepts easy to follow. No prior knowledge of FreeMASTER is required — by the end, you’ll understand what the tool does and why it’s useful.
The dashboard the car project shown below was built using FreeMASTER, offering a powerful way to visualize and interact with embedded system data in real time. Dynamic gauges, graphs, and control panels create an intuitive interface that bring the application to life
Figure 1. Demo Car Project
A short demo video showcasing FreeMASTER highlights how easily you can monitor variables, tune parameters, and build a fully functional automotive dashboard, making it an excellent tool to accelerate development and spark interest in your own project.
Figure 2. FreeMASTER Dashboard – in action
Overview
This article introduces basic FreeMASTER concepts to give the readers a glimpse of what FreeMASTER is about, its components and capabilities. Later, it will follow up with:
- FreeMASTER block in Simulink – We will explain how FreeMASTER is enabled and configured on the embedded device in Simulink using NXP’s Model Based Design Tools.
- Data visualization and control in FreeMASTER – We will use the FreeMASTER desktop tool to connect to the embedded application developed in the previous step and visualize variables using Windows native controls.
- Web dashboards with FreeMASTER Lite – We will introduce FreeMASTER Lite and the JSON-RPC API that will help us build a custom dashboard and interact with the embedded application directly from a web browser.
What is FreeMASTER?
FreeMASTER is a user-friendly real-time debugging tool. At the core, it allows users to read and write embedded variables from a GUI – desktop tool or a web interface. Unlike an actual debugger, FreeMASTER does not interrupt application execution and supports multiple communication interfaces such as UART, USB-CDC, CAN, TCP/IP, JTAG/BDM, and others.
Why and when to use FreeMASTER?
FreeMASTER is not limited to a particular usage. This section highlights 3 use-cases, to set a starting context that, once understood, can be adjusted to user specific needs.
Embedded application debugging tool
During the embedded application development process, the tool helps developers to:
- monitor variables to ensure correct execution flow
- simulate various scenarios by adjusting variable values and verify that those are properly handled by the firmware
Figure 3. FreeMASTER as an embedded application debugging tool
Run-time Configuration and Tuning Tool
With FreeMASTER, engineers can implement flexible firmware for embedded targets that can be adjusted to various scenarios. If the application implements a parametrizable algorithm or a state machine, FreeMASTER can help to:
- execute various tuning flows to identify the optimal configuration for the customer’s scenario
Figure 4. FreeMASTER as a run-time configuration and tuning tool
Framework for Interactive Dashboards
FreeMASTER can bridge the gap between technical and non-technical users by offering functionality that can engage the latter category via interactive applications. Developers can make full use of modern web technologies to create interactive user interfaces for the embedded applications either via the tool’s embedded web browser or the exposed JSON-RPC API.
Figure 5. FreeMASTER as a framework for interactive dashboards
Context
FreeMASTER consists of 2 primary components:
- FreeMASTER Driver – small library that goes into the embedded application. Its base functionalities are reading and writing memory locations corresponding to application variables.
- FreeMASTER – desktop tool that runs on a Windows PC. It allows users to visualize and edit embedded application variables in a Graphical User Interface or via a JSON-RPC API (a higher-level interface for the low-level FreeMASTER protocol).
Figure 6. FreeMASTER master-slave communication architecture
At the core, both components implement a proprietary serial communication protocol based on a master-slave architecture. In this model, the PC tool – master, issues commands requesting data. The target board – slave device, responds only when addressed by the master and cannot initiate communication independently.
When the user interacts with FreeMASTER’s Graphical User Interface (e.g. adds a variable to plot or edits a table cell corresponding to a variable value), the tool converts the action into a command that is sent to the target board via the FreeMASTER protocol. The same happens when users consume the JSON-RPC API.
At the same time, on the embedded side, FreeMASTER Driver routines listen to incoming messages. Once a message is received, it is processed and the return status with the result (if any) is sent back to the host PC and ultimately visualized in the UI or forwarded via the JSON-RPC API to the consumer (client application).
Conclusion
FreeMASTER is a powerful data visualization tool from NXP that helps users monitor and control embedded applications.
In the next article, we will introduce the Simulink block from NXP’s Model-Based Design Tools that facilitates the FreeMASTER Driver integration into applications developed in the MATLAB environment.
