I’m in the middle of the university exam season: means writing exams and do grading. The same time the new semester is approaching too and I need to prepare the new course material. For the classes using NXP parts I’m using the Eclipse based MCUXpresso IDE, and I just received the announcement that a new version V11.3.0 is available: time to check out what is new.
The Eclipse CODAN (Code Analysis) plugin is part of CDT and is a powerful static analysis tool finding all kind of possible bugs and issues. Still to my surprise not many C/C++ developers take advantage of it maybe because they are not aware that it exists?
In this article I show a few tips how to effectively use it, especially with the NXP MCUXpresso SDK.
The NXP Kinetis devices implement a UID (Unique ID) for each device, using the ‘Unique Identification Register) which is part of the SIM (System Integration Module):
While this number should be unique, I was wondering last week why students in the labs reported the same UID for multiple robots in the lab. So maybe this number is not so unique as it should be?
Reentrancy is an attribute of a piece of code and basically means it can re-entered by another execution flow, for example by an interrupt or by another task or thread. This is an important concept and still a lot of code ‘in the wild’ does violate reentrancy. As a result the application crashes immediately in the best case. Worse it crashes randomly or even worse it behaves incorrectly 😦 .
Reentrancy is always a concern if using standard library functions, including printf() or malloc(). FreeRTOS offers a reentrant wrapper to the standard malloc() and free() (Memory Scheme 3)
If having a boot loader running on a micro-controller, it is very useful if both the boot loader and the loaded application can be debugged together:
The tinyK22 board is a tiny micro controller board we use at the Lucerne University of Applied Sciences and Arts. It is used in many research project, used in lectures and labs and used in most student projects. Because there was no small and breadboard friendly NXP Kinetis board with a debug interface available, we developed one featuring the NXP K22FN512, named the ‘tinyK22‘. Because of the success and high demand we stated a new large production run and used this to upgrade the board to the new Rev 1.3: you might notice already the color change :-).
Eclipse has a great built-in source code parser and browser (aka ‘Indexer’). It is basically a built-in compiler which parses the source files and assists the user with code completion and navigation help, making Eclipse this awesome productivity tool. On the downside this background parsing could potentially slow down things, and therefore Eclipse has some default settings to prevent this. Unfortunately, the FreeRTOS Kernel ‘tasks.c’ file is above-and-beyond of a ‘sane’ source file and will hit the default limits: as a result the ‘tasks.c’ file is not indexed and things like ‘Open Declaration‘ might not work for the file ‘tasks.c’.
Typically I have many, many projects listed in the Eclipse Project Explorer, usually more than 100 projects: from example projects, projects on git, lecture module projects, research projects or just some hobby projects I’m working on. With the default Eclipse settings, all these projects are listed in a ‘linear’ list. What I found really useful is the ability to group them into ‘Working Sets‘:
As a VCS (Version Control System) I’m using git in all my projects. And not only for software or firmware projects: I’m using it for hardware design (KiCAD, FreeCAD, …) or for documentation (LaTeX, …) too.
The nice thing with the Eclipse IDE is that it supports nice git integration, making importing projects from git repositories easy.
COVID-19 is by far not over, and in Switzerland the infection rate is going up again (2nd wave?). During the spring 2020 semester university lock-down we moved pretty much everything to a ‘distance learning’ setup. With that experience and with the request to prepare for the fall semester, I have constructed a DIY conference and teaching device which should make things simpler and easier: a combination of video camera, speaker phone and a muting device: