Using Multiple Memory Regions with the FreeRTOS Heap

ARM Cortex-M microcontrollers can have multiple memory controllers. This is a good thing as it allows the hardware to do multiple parallel memory read/writes. However this makes the memory map more complicated for the software: it divides the memory into different regions and memory segments.  This article is about how to enable FreeRTOS to use multiple memory blocks for a virtual combined memory heap:

FreeRTOS with Segmented Heap Memory

FreeRTOS with Segmented Heap Memory

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Tutorial: Porting BLE+NRF Kinetis Design Studio Project to MCUXpresso IDE

The tools and IDE market is constantly changing. Not only there is every year at least one new major Eclipse IDE release, the commercial tool chain and IDE vendors are constantly changing the environment too. For any ARM Cortex-M development, the combination of Eclipse with the GNU tool chain provided by ARM Inc. is the golden standard. But this does not mean that things can be easily moved from one IDE package to another.

While moving between Eclipse versions and GNU versions is usually not a big deal at all, moving between the Eclipse build tool integration is usually not simple. While the GNU MCU Eclipse plugins are widely used (see Breathing with Oxygen: DIY ARM Cortex-M C/C++ IDE and Toolchain with Eclipse Oxygen), the Eclipse based IDEs from the silicon vendors or commercial Eclipse toolchain vendors are using  their own GNU toolchain integration. Which means the project files are not compatible :-(.

NXP FRDM-KW41Z Board

NXP FRDM-KW41Z Board

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Why you should not use Arduino for Professional Work

Have a read at http://embedded.fm/blog/2017/8/12/dont-use-arduino-for-professional-work.

I love the Arduino ecosystem, and it is great for getting something up and running quickly for a ‘proof of concept’. But it stops at that point.

I think it should be obvious why Arduino (code and libraries) should not be used for professional work. Especially the lack of proper debugging support makes it nearly impossible to solve the problems of the real world.’printf()’ style of debugging is simple, but it is a huge waste of time. I have seen too many student projects failing because the inability to properly debug the system and solve the problems.

Even equally important for professional work is the topic of IP and licensing. Be aware of the licensing terms and conditions as pointed out by above article. If not, your product easily get GPL’d which might not want you want.

Arduino

Arduino

Happy Arduinoing 🙂

Adding CMSIS-SVD Files to EmbSysRegView 0.2.6.r192 and Eclipse

In “EmbSysRegView 0.2.6 for Eclipse Neon and Oxygen” I have described how to add CMSIS-SVD register detail files to Eclipse using the EmbSysRegView plugin.

But what I need to add vendor or any other SVD files to it? Here is how:

EmbSys Registers View

EmbSys Registers View

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Building Eclipse and MCUXpresso IDE Projects from the Command Line

Eclipse as IDE takes care about compiling and building all my source files. But in an automated build system I would like to build it from the command line too. While using make files (see “Tutorial: Makefile Projects with Eclipse“) is an option, there is another easy way to build Eclipse projects from the command line:

Building MCUXpresso IDE from Command Line

Building MCUXpresso IDE from Command Line

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Breathing with Oxygen: DIY ARM Cortex-M C/C++ IDE and Toolchain with Eclipse Oxygen

Last month (June 2017), the latest version of Eclipse “Oxygen” has been released, and I have successfully used it in several embedded projects. Time to write a tutorial how to use it to build a custom Do-It-Yourself IDE for ARM Cortex-M development: simple, easy, unlimited and free of charge. While the DIY approach takes a few minutes more to install, it has the advantage that I have full control and I actually know what I have.

Eclipse Oxygen

Eclipse Oxygen

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Custom 3D Printed Enclosure for NXP LPC-Link2 Debug Probes

I love 3D printing as it enables me to create custom enclosures for all kind of projects. The NXP LPC-Link2 probe is great, but it lacks a protective enclosure. So I decided to create a custom enclosure. And as 3D filaments are available in different colors, I experimented with red and black and custom painting:

lpc-link2 enclosure

lpc-link2 enclosure

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Troubleshooting Tips for FreeRTOS Thread Aware Debugging in Eclipse

FreeRTOS seems to get more and more popular, and I think as well because more and more debugger and Eclipse IDE vendors add dedicated debugging support for it.

FreeRTOS Threads in Eclipse

FreeRTOS Threads in Eclipse

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How to use Custom Library Names with GNU Linker and Eclipse

By default, the GNU Linker expects a very special naming scheme for the libraries: the library name has to be surrounded by “lib” and the “.a” extension:

lib<NAME>.a

But what if the library I want to use does not conform to that naming standard?

Non-conforming Library Naming

Non-conforming Library Naming

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Tutorial: Makefile Projects with Eclipse

The benefit of an IDE like Eclipse is: it makes working with projects very easy, as generates make files and it takes and automatically manages the make file(s). But sometimes this might not be what I want because I need greater flexibility and control, or I want to use the same make files for my continues integration and automated testing system. In that case a hand crafted make file is the way to go.

One thing does not exclude the other: This article explains how to use make files with Eclipse with similar comfort as the managed build system in Eclipse, but with the unlimited power of make files:

Makefile Project with Eclipse

Makefile Project with Eclipse

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MCUXpresso IDE v10.0.2 – Updated Eclipse based IDE for LPC and Kinetis

NXP has released an updated of their Eclipse based IDE for ARM Cortex-M (Kinetis and LPC) microcontroller: the version v10.0.2 build 411:

MCUXpresso v10.0.2 build 411

MCUXpresso v10.0.2 build 411

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Getting Started: ROM Bootloader on the NXP FRDM-KL03Z Board

A bootloader on a microcontroller is a very useful thing. It allows me to update the firmware in the field if necessary. There are many ways to use and make a bootloader (see “Serial Bootloader for the Freedom Board with Processor Expert“). But such a bootloader needs some space in FLASH, plus it needs to be programmed first on a blank device, so a JTAG programmer is needed. That’s why vendors have started including a ROM bootloader into their devices: the microcontroller comes out of the factory with a bootloader in FLASH. So instead writing my bootloader, I can use the one in the ROM.

FRDM-KL03Z with ROM Bootloader

FRDM-KL03Z with ROM Bootloader

And as with everything, there are pros and cons of that approach.

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Compiler Explorer

If you are like me – someone who always wants to know what the compiler generates for a piece of source code – then have a look at the Compiler Explorer: A web-based compiler code comparison tool:

Compiler Comparison

Compiler Comparison

Thanks to Matt Godbolt, I can select different compilers and compare their output for a given source code. Very useful to see the impact of a compiler optimization or to compare different GCC compiler versions.

Happy Comparing 🙂

Using FreeRTOS with newlib and newlib-nano

For reliable applications, I avoid using functions of the standard libraries. They are banned for most safety related applications anyway. I do not use or avoid malloc(), printf() and all the other variants, for many reasons including the ones listed in “Why I don’t like printf()“. Instead, I’m using smaller variants (see “XFormat“). Or I’m using only the thread-safe FreeRTOS heap memory allocation which exist for many good reasons.

Things get problematic if malloc() still is pulled in, either because it is used by a middleware (e.g. TCP/IP stack) or if using C++. Dave Nadler posted a detailed article (http://www.nadler.com/embedded/newlibAndFreeRTOS.html) about how to use newlib and newlib-nano with FreeRTOS.

FreeRTOS Newlib Memory Allocation Scheme

FreeRTOS Newlib Memory Allocation Scheme

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First Steps with the Variscite DART-6UL i.MX6 UltraLite Development Kit

For a next-gen course I’m evaluating different platforms, and one of it are modules based on the NXP i.MX ARM architectures. In this article I have a look a the Variscite DART-6UL development kit which includes the NXP i.MX6Ultralite ARM Cortex-A7 plus a 7″ capacitive touch LCD:

Variscite VAR-DVK-6UL_LO Kit

Variscite VAR-DVK-6UL_LO Kit

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GNU Code Coverage on Embedded Target with Eclipse Neon and ARM gcc 5

For a research project, we are going to send a satellite with an embedded ARM Cortex microcontroller into space early next year. Naturally, it has to work the first time. As part of all the ESA paperwork, we have to prove that we tested the hardware and software thoroughly. One pice of the that is to collect and give test coverage evidence. And there is no need for expensive tools: Free-of-charge Eclipse and GNU tools can do the job for a space mission 🙂

Eclipse with Coverage Views

Eclipse with Coverage Views

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Using Python to Store Data from many BLE Devices

BLE (Bluetooth Low Energy) sensor devices like the Hexiwear are great, but they cannot store a large amount of data. For a research project I have to collect data from many BLE devices for later processing. What I’m using is a Python script running on the Raspberry Pi which collects the data and stores it on a file:

Raspberry Pi with Python controlling a set of Hexiwear BLE Devices

Raspberry Pi with Python controlling a set of Hexiwear BLE Devices

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DIY USB HID Joystick Device and Game Controller

For many projects it would be cool to build a custom USB Joystick device, either as custom game controller for Windows or any USB host which can be used with a USB Joystick. Instead buying one, why not build my version? All what I need is a USB capable board, some kind of input (potentiometer, push buttons) and some software, and I have my USB Joystick:

DIY USB HID Joystick Device

DIY USB HID Joystick Device

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ARM SWO Performance Counters

In “Cycle Counting on ARM Cortex-M with DWT” I have used the ARM DWT register to count the executed cycles. With the MCUXpresso IDE comes with a very useful feature: it can capture the ARM SWO (Single Wire Output) trace data. One special kind of trace data is the ‘cycle counter’ information which is sent through SWO.

SWO Counters

SWO Counters

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