FreeMASTER 3.1.3 Update - Release Announcement

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FreeMASTER 3.1.3 Update - Release Announcement

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FreeMASTER 3.1.3 Update - Release Announcement

Version 3.1.3 of the NXP FreeMASTER tool has just been published online. 

This version is backward compatible and fully replaces older 3.1.x releases (see previous announcements). The latest version brings new features and bugfixes described below.

The updated installer is available along with documentation and other resources at 

Release description

 is a powerful data visualization tool developed and provided by NXP to help users monitor and control embedded applications running on NXP’s targets. It works with almost all NXP Arm ® Cortex®-M microcontrollers from both Edge Processing and Automotive business lines as well as with DSC and legacy Power Architecture, ColdFire and HCS12/Z platforms. Note that the license terms and conditions does not allow using FreeMASTER with non-authorized systems from other vendors.

Version 3.1.3 is a minor update of the 3.1.x mainline release line. If there is any previous 3.1.x version already installed on the host computer, the FreeMASTER 3.1.3 overwrites the installation and it remains referred as a general mainline version 3.1. Older 2.x and 3.0 versions are not removed. 

Version 3.1.3 is backward compatible with all previous versions. It supports variable monitoring, oscilloscope real time graphs, fast transient recorder graphs and connectivity to 3rd party applications. An HTML rendering engine based on Chromium with full support of JSON-RPC, HTML5 and JavaScript is available to create custom dashboards and other user interfaces that can run inside FreeMASTER or standalone in local or remote web browser. Older Internet Explorer rendering, ActiveX interface and protocols defined for versions 2.x are also still supported.

FreeMASTER Lite service which is part of the FreeMASTER installation package provides the communication core for Windows and Linux systems. It is accessible similarly as the FreeMASTER desktop application over the JSON-RPC interface. FreeMASTER Lite also embeds the popular Node-RED framework for graphical programming and provides many examples of use with the FreeMASTER tool. Find more information related to Node-RED in the dedicated training video

Note: Installing FreeMASTER Lite will require you to enter an activation code. Get your free code on the License Keys tab at the license information page.

FreeMASTER Node.js Installable Modules enable convenient use of the FreeMASTER JSON-RPC components in a Node.js applications managed by the ‘npm’ package manager.

New Features

Version 3.1.3 introduces brand new features extending data visualization and communication options:

Communication over Segger RTT JLink interface

New option was added in the network plug-in to enable communication over Segger RTT interface. Segger J-Link RTT is a high-speed bi-directional stream communication between host PC and target ARM CortexM CPU. A telnet protocol is used on the host PC to reach out to the J-Link interface so this communication may also be established to a remote computer's J-Link probe.

Key benefit of the RTT is that the communication may be used simultaneously with an active debugger session established over the same J-Link interface.

The network plug-in has been released in previous 3.1.2 version and enables a direct network communication with a target MCU using UDP or TCP protocols. The new version extends this plug-in by an RTT communication option.

The ‘fmstr_rtt’ example application for i.MX-RT and other supported MCU platforms is going to be available soon in the FreeMASTER driver v3.0.5 available in MCUXpresso SDK version 2.11.

ActiveX and JSON-RPC Server optimization

Performance of the ActiveX and JSON-RPC servers accessed from external 3rd party clients is improved by running the internal COM+ server in a background thread, independent on the main UI processing.

Comparing it to older implementation, the 3rd party clients like Excel, Matlab, or Chrome web browser application interact faster with FreeMASTER back end as the communication is no more handled in the main UI process.

FreeMASTER Lite middleware optimization

Previously used FFI (Foreign Function Invocation) module was replaced with Node Native Addons. This change reduces the delay of invoking mcbcom library functions.

Additionally, embedded NodeJS was upgraded from v12 (EOL) to v16.

Note: since version 14, NodeJS supports Windows 8 and newer. This applies to FreeMASTER Lite as well, considering it is now using NodeJS v16.

Using multiple FreeMASTERs

Both ActiveX and JSON-RPC clients are now better able to access multiple instances of the running FreeMASTER tool and access multiple MCU applications in parallel. Please refer to detailed information and examples provided in the User Guide.

Other changes

List of other minor changes in version 3.1.3

  • Support for drag&drop re-positioning of variables has been enabled in the Variable Watch grid view.
  • HTML applications running inside the FreeMASTER window may now access a special URL to retrieve a “info.js” file which defines a JSON object with various information about the currently running process, active project, communication settings etc. Refer to User Guide for more information.

Bugfixes and other extensions:

  • Fixed false recorder error when a variable is added as hidden & non-triggering.
  • Fixed recorder setup dialog to prevent adding trigger variable without polarity defined.
  • Fixed recorder state machine bug causing recorder to get stuck when manually aborted.
  • Fixed ELF parser to load all C++ base-class members in case of indirect inheritance DWARF entry is used.
  • Fixed inconsistent behavior of ELF parser when loading C++ class types, behaving differently after FreeMASTER startup and after ELF file was reloaded.
  • Fixed SelectItem RPC call, could crash when bad item name was specified.
  • Fixed maximum number of threads that can connect to communication DLL when communicating over a plug-in. Number increased from 4 to 16. Small number was causing issues when accessing communication from a Chromium engine.

Release target audience

Both FreeMASTER and FreeMASTER Lite are primarily targeted to our customers, engineers and developers of NXP embedded applications from Industrial, IoT and Automotive areas who want to monitor and control their applications at runtime. FreeMASTER is also a strong framework which can be used to create interactive demos and user interfaces helping to use the embedded applications by yet wider target audience.


FreeMASTER tools run on the host computer and communicate with the target microcontroller application using Serial, CAN, Ethernet/WiFi network, JTAG, BDM or other physical interface. The microcontroller communication drivers are available as part of MCUXpresso SDK, S32 Design Studio or as a standalone installation package. Get familiar with the communication protocol and the microcontroller driver API before using the FreeMASTER tool.

License terms and conditions permit use of FreeMASTER solely with systems based on NXP microprocessor or microcontroller systems.


A single self-extracting installation package which contains both FreeMASTER desktop application and the new FreeMASTER Lite service is available for Windows platforms. A package with the FreeMASTER Lite service is also available for Linux.
Access the installation and documentation at the FreeMASTER home page at

Version history
Last update:
‎10-29-2021 06:22 AM
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