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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MCUXpresso SDK Tutorial – using I2C Driver on OKdo E1 board

In an earlier tutorial I introduced using I2C with the NXP LPC55S69 on OKdo E1 board to read a Bosch BME280 environmental sensor on a Mikroe Weather Click board. The MCUXpresso Clocks, Pins and Peripheral Config tools were used to get it running. It’s all for my Weather Station project that I’ve been working on during these months of lockdown. It is starting to take shape – as you can see from the photograph:

From the left: Mikroe Weather Click, OKdo E1, Mikroe eInk Click.

Now I really need to start reading and writing to the BME280 sensor, and that means using the I2C driver in the lpcxpresso55s69 SDK. And so this week I’ll provide a forensic examination of the most commonly-used I2C function call.

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MicroTick (UTICK) Timer Tutorial with OKdo E1 board

I want to share with you a little embedded trick that I use to improve the reliability of my code. And in addition to improving reliability, the technique can be used to schedule any event to occur ‘sometime in the future’. It uses the MicroTick (UTICK) timer found on the NXP LPC55S69 microcontroller, and could be applied to any device with a simple timer.

The MicroTick timer is an elegant, thing of beauty. But there is not a driver example built into the lpcxpresso55s69 SDK, and I believe that the timer is not widely used. That means we need a tutorial!

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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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MCUXpresso tutorial: I2C using the Pins/Clocks/Peripherals Config tools and lpcxpresso55s69 SDK

I selected the Bosch BME280 environmental sensor as the heart of my OKdo E1-based weather station. It is convenient to use, and I can prototype with the Mikroe Weather Click board MIKROE-1978. But the sensor is accessed over I2C, and that is my least favourite of the communication interfaces. In this short tutorial, I show you how the MCUXpresso Config tools (Pins, Clocks, Peripherals) are used to set up the I2C driver from the MCUXpresso lpcxpresso55S69 SDK. And very quickly, I am able to communicate with the BME280 sensor.

Reading BME280 “ID” register via I2C
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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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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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First experience with OKdo E1 board

This week I’m sharing my experience “getting started” with the OKdo E1 board. This board, featuring the NXP LPC55S69 150 MHz, dual Cortex M33 core microcontroller was a joy to use. OKdo have provided an online Getting Started guide, and I’ve field-tested this for you. My video tutorial recorded as I follow the guide is less than 7 minutes long… it may take you a little longer if you need to download MCUXpresso IDE or the lpcxpresso55s69 Software Development Kit (SDK) but I am confident that you will quickly have the board up-and-running.

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Retrofitting a Charmhigh CHM-T36VA Machine with OpenPnP

OpenPnP is a great open source framework for building a DIY SMT Pick&Place machine. But it does not stop there: It is possible to use OpenPnP with a commercial pick & place machine, for example the Charmhigh CHM-T36VA. This Chinese machine comes with its own controller software which works but is not that great. The good news is that it is possible to hack and retrofit the machine so it can run the much more powerful OpenPnP.

Retrofitted CHM-T36VA

Retrofitted CHM-T36VA

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Dumping Variables and Arrays with GDB in Eclipse

Using the debugger to inspect the application data is a very convenient thing. But if the data grows and if the data set is large, it makes more sense to dump the data to the host and process it offline. GDB is the de-facto debugger engine and includes a powerful command line and scripting engine which can be used in Eclipse too.

GDB Debugger Console in Eclipse

GDB Debugger Console in Eclipse

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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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Tutorial: Maximum Clock Frequency for Kinetis using MCUXpresso Clock Tools

The tinyK22 board with the NXP K22FN512 is a bread-board-friendly small board with a 8 MHz external oscillator:

tinyK22 Board

tinyK22 Board

This tutorial is about how to use the NXP MCUXpresso Clock configuration and configure the board to the maximum clock frequency of 120 MHz. The same steps apply to many other boards, including the FRDM-K22F one.

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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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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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DIY ‘Meta Clock’ with 24 Analog Clocks

Human since 1982 claims

“Human since 1982 have the copyright to works displaying digital time using a grid arrangement of analog clocks…”

I’m not a lawyer, but without obligations (imho) I have removed the content.

Thanks for understanding,

Erich