DIY Portable Video Conference, Sharing and Teaching Device

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:

Desk with Communicator

Desk with Communicator C2020

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MCUXpresso IDE V11.2.0

At the university the end of a semester means that you have to get ready for the next semester. I always tend to use the latest and greatest tools for the labs. This week I received the notification that a new version of the Eclipse based MCUXpresso IDE is available, time to check it out for the next semester.

MCUXpresso IDE 11.2.0

MCUXpresso IDE 11.2.0

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Eclipse Gems, Tips & Tricks: Faster Debugger Start

This article is part of a ‘mini series’ about hidden gems, tips and tricks around Eclipse.
The topic of this one is how to accelerate the start of the debugger.

Nothing to be done

Nothing to be done

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From C to C++: Converting Eclipse C Projects

Creating a new project with Eclipse for a microcontroller these days is fairly easy, and I have the choice if I want to start the project with C or C++:

Choice of C and C++ for a new project

Still the embedded microcontroller world is dominated by C and not C++. So while it is easy to start with a C++ project, most vendor provided example or tutorial project are C projects. So how can I transform such project to C++?

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How to use Eclipse CDT Environment Variables in C/C++ Code

When using a logging framework it is useful to use the current file name or line number. The ANSI C/C++ standard defines the __LINE__ and __FILE_ preprocessor macros for this.

But what about the project name, if it is a release or debug build, the microcontroller used or other things like the operating system which was used to build the binary?

Target Chip Name

Target Chip Name

This (and even more) can be easily provided by Eclipse to the C/C++ application being built with CDT.

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How to get Data off an Embedded System: FatFS with USB MSD Host and FreeRTOS Direct Task Notification

This is a follow-up article of my earlier project presented in “FatFS, MinIni, Shell and FreeRTOS for the NXP K22FN512“. I wanted to extend it with a USB MSD (memory stick) device: The USB storage device gets automatically mounted, and depending on a configuration (.ini) file on the memory device I can perform various actions, for example automatically copy data from the SD card to the USB device. For example the system logs data, and to get the data I insert the memory stick, it copies the data on it and automatically unmounts it, and I can remove the memory stick.

FRDM-K22F USB Host Mode with Memory Sticks

FRDM-K22F USB Host Mode with Memory Sticks

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Disabling NMI (Non Maskable Interrupt) Pin

The NMI is a special interrupt on ARM Cortex-M architecture: as the name indicates, it cannot be ‘masked’ by the usual ‘disable interrupts’ flags (PRIMASK, BASEPRI), similar to the Reset signal.

cortex-m-vector-table

cortex-m-vector-table (Source: adapted from arm.com)

Dealing with the reset signal is kind of obvious, and most designs and boards have it routed to a reset button or similar. The NMI is less obvious if you don’t pay attention to it: most ARM-Cortex implementations and boards have the NMI signal routed to a pin and are ‘hiding’ it in the schematics behind a normal GPIO pin or port: if you don’t pay attention to the NMI functionality, the board might not work as intended.

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Behind the Canvas: Making of “60 Billion Lights”

As promised I’m going to share more details about the “60 Billion Lights” project. It is about a project to build a piece of electronics behind a 100×50 cm canvas to show animations or to display information like temperature, humidity, weather, time or just any arbitrary text.

Make it

Writing text

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McuLog: Logging Framework for small Embedded Microcontroller Systems

An essential tool especially developing larger applications or distributed firmware is to use logging. This article presents an open source logging framework I’m using. It is small and easy to use and can log to a console, to a file on the host or even to a file on an embedded file system as FatFS.

Log Output

Log Output

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Tutorial: Adding FreeRTOS to where there is no FreeRTOS

FreeRTOS is pretty much everywhere because it is so simple and universal, and it runs from the smallest to the biggest systems. But it still might be that for the microcontroller device you have selected there is no example or SDK support for it from your vendor of choice. In that case: no problem: I show how you could easily add FreeRTOS plus many more goodies to it.

Binky on NXP LPC845-BRK Board

Binky on NXP LPC845-BRK Board

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“60 Billion Lights”: 2400 RGB LEDs and 120 Stepper Motors hiding behind Canvas Art

It is one thing to create something ‘cool’ or technically interesting. But it is a completely different story to convince your girlfriend, partner, wife, family (or whatever you can name it) to hang something on a wall in our house or office. Then it is not about technology: it is more about design and art. So here is my attempt to solve that challenge:

Displaying current temperature

Displaying temperature with a painted canvas, stepper motors and 2400 RGB LEDs

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FatFS, MinIni, Shell and FreeRTOS for the NXP K22FN512

I’m using the NXP Kinetis K22FN512 in many projects, either with the FRDM-K22F or on the tinyK22: with 120 MHz, 512 KByte FLASH and 128 KByte it has plenty of horsepower for many projects. The other positive thing is that it is supported by the NXP MCUXpresso IDE and SDK. I have now created an example which can be used as base for your own project, featuring FreeRTOS, FatFS, MinIni and a command line shell.

FRDM-K22F with SD Card

FRDM-K22F with SD Card

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FreeRTOS Task Runtime Statistics for NXP i.MX RT1064

FreeRTOS has many cool features, and one is that it can report the CPU percentage spent in each task. The downside is that to get this kind of information some extra work is needed. In this article I show how to do this for the NXP i.MX1064.

FreeRTOS Runtime Information

FreeRTOS Runtime Information

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Tutorial: Rename, Copy or Clone Eclipse Projects with MCUXpresso

Especially in a lab or classroom environment it is convenient to start with a template project, and then explore different ways to shape the project for different needs. As for any IDE of this world, this requires an understanding of the inner workings to get it right. So in this article I show how to copy, clone or rename properly an Eclipse ‘template’ project in the MCUXpresso IDE.

Template Project

Template Project

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Visualizing Data with Eclipse, gdb and gnuplot

The gnuplot is a versatile and powerful tool to plot and visualize all kind of data. I wish there would be a plugin for it in Eclipse. But as this is not (yet?) the case, here is how I’m using it with gdb and Eclipse, using the MCUXpresso IDE as example.

Gnuplot with Eclipse

Gnuplot with Eclipse

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Enable Default FreeRTOS Debugging for LinkServer Debug Connections

Most of my projects are using FreeRTOS, and I’m using different Debug Probes (SEGGER, P&E and LinkServer) to debug NXP devices.

The NXP LinkServer debug connection is able to show the RTOS threads in Eclipse/MCUXpresso IDE which is incredibly helpful:

FreeRTOS Thread Aware Debugging with LinkServer Connection

FreeRTOS Thread Aware Debugging with LinkServer Connection

However, by default this is turned off. In this article I show how to turn this on by default.

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Ways to apply Eclipse CDT C/C++ Project Settings

Eclipse with its CDT managed Make system makes it easy to build projects, because it can handle a lot of the background tasks and settings between the project and the build setting. It can get a bit difficult if I want to include a library or other sub-source project for which I have to add extra compiler #define or add extra includes path settings.

Eclipse project settings for incliude paths

Eclipse project settings for include paths

This article show the different ways I have found to make such imports (and exports) easier.

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Listing Code and Data Size for all Files with the GNU size Utility in a Post-Build Action

The GNU size utility which is part of the GNU build tools shows code and data size for archive or object files. It is usually used as a post-build step in Eclipse CDT to show text, data and bss at the end of the build:

Detailed size information for each file

Detailed size information for each file

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MCUXpresso IDE V11.1.0

Right before Christmas 2019, NXP has released a new version of the MCUXpresso IDE, the version 11.1.0. This gave me time to explore it over the Christmas/New-Year break and evaluate it for the next university semester. There are several new features which will make my labs using it easier, so I plan to get the course material updated for it.

MCUXpresso IDE V11.1.0 Welcome Screen

MCUXpresso IDE V11.1.0 Welcome Screen

After the break you will find the highlights …

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Implementing FreeRTOS Performance Counters on ARM Cortex-M

When using an RTOS like FreeRTOS, sooner or later you have to ask the question: how much time is spent in each task? The Eclipse based MCUXpresso IDE has a nice view showing exactly this kind of information:

FreeRTOS Runtime Information

FreeRTOS Runtime Information

For FreeRTOS (or that Task List view) to show that very useful information, the developer has to provide a helping hand so the RTOS can collect this information. This article shows how this can be done on an ARM Cortex-M.

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