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

Investigating ARM Cortex® M33 core – WiFi with Mikroe WiFi 10 click board

For this last blog in the series Investigating ARM Cortex® M33 core I decided to explore the expansion features of the LPC55S69-EVK. This board has three expansion ports (PMOD, Arduino Duo, Mikroe click) and I picked the Mikroe expansion port. Why? Only because I had good experience with these boards with the Hexiwear project.

And because I have been doing some work this month with AWS IOT I wanted to get my LPC55S69-EVK onto my office WiFi network for the Christmas holidays. I know that the MCUXpresso SDK for lpcxpresso55s69 version 2.6.3 has a built-in WiFi example named qca_demo, and so that is what I am investigating today.

That WiFi example supports three WiFi shield boards, and I picked the Mikroe WiFi 10 click board. It’s part number MIKROE-3432 and available from all of the usual catalogue distributors.

WiFi 10 click board from Mikroelektronika
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Investigating ARM Cortex® M33 core – Dual Core debug tutorial

In last week’s blog I explained that the LPC55S69 microcontroller from NXP has two Cortex® M33 cores, named core0 and core1. There was a lot of theory, and so this week I put it all into practice and show you how to debug 2 cores with MCUXpresso IDE.

Multicore Debugging Interface in MCUXpresso IDE showing 2 different projects
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Investigating ARM Cortex® M33 core – NXP LPC55S69 has *two* M33 cores.

Throughout this series I’ve been using the LPC55S69 microcontroller from NXP as a platform to investigate the ARM Cortex® M33 core. NXP designed the LPC55S69 with two Cortex M33 cores and so this week I’m investigating these in more detail.

You’ll remember that when ARM launch a processor core it will have a number of optional features. This is shown very clearly on the LPC55S69. The 150 MHz primary core – cpu0 – is a full implementation of Cortex® M33 and includes the optional components FPU, MPU, DSP, ITM and the TrustZone® features.

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Investigating ARM Cortex® M33 core – DSP Acceleration 3 (PowerQuad FFT Tutorial)

I’ve always felt that the Fourier Transform (and in particular the embedded implementation Fast Fourier Transform) is the GOAT* of the DSP algorithms. The ability to convert a time-domain signal into a frequency-domain signal is invaluable in applications as diverse as audio processing, medical electrocardiographs (ECGs) and speech recognition.

So this week I’ll show you how to use the Transform engine in the PowerQuad on LPC55S69 to calculate a 512-point FFT. All of the difficult steps are very easily managed and the PowerQuad does all of the very heavy lifting.

Data from PowerQuad – 512-point real FFT on 400 Hz input signal with 1200 Hz harmonic
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Investigating ARM Cortex® M33 core – DSP Acceleration 2 (PowerQuad Matrix Engine Tutorial)

Last week I showed you how to use the Coprocessor interface of PowerQuad to calculate (mostly) unary functions. As an example the natural logarithm ln(x) takes just one operand, whilst the floating divide in PowerQuad requires two operands (x1)/(x2). PowerQuad is very efficient accelerating these functions, requiring just 6 clock cycles for the ln(x) and 6 clock cycles for the float (x1)/(x2). In comparison the single-precision floating point unit in Cortex® M4F and M33F requires 13 clock cycles to perform the same float divide.

But there are two ‘sides’ to the PowerQuad:

  • The Coprocessor interface, using ARMv8-M coprocessor instructions;
  • The AHB bus interface, where we address PowerQuad as a peripheral.

So this week… operating the PowerQuad as a peripheral. I’ll show you how to use the PowerQuad SDK driver in MCUXpresso in a new project, and use the Matrix Engine in the PowerQuad to solve simultaneous equations.

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