The ARM mbed USB MSD bootloader which is used on many silicon vendor boards has a big problem: it is vulnerable to operating systems like Windows 10 which can brick your board (see “Bricking and Recovering OpenSDA Boards in Windows 8 and 10“). To recover the board, typically a JTAG/SWD programmer has to be used. I have described in articles (see links section) how to recover from that situation, including using an inofficial new bootloader which (mostly) solves the problem. The good news is that ARM (mbed) has released an official and fixed bootloader. The bad news is that this bootloader does not work on every board because of a timing issue: the bootloader mostly enters bootloader mode instated executing the application.
I’m pleased to announce that a new release of the McuOnEclipse components is available in SourceForge. It this release more ARM Cortex devices/vendors are supported with different SDKs, plus it comes with several FreeRTOS enhancements for debugging highly optimized code.
For several projects I’m using library projects: I build a library and then use that library in the other project. If I change something in a library, I want to run make both on the referenced libraries and rebuild my application if needed. If you don’t know how to do this, then read on… 🙂
Shared Library Projects
(… actually it means workign around known Eclipse CDT bug too….)
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:
Many of the NXP OpenSDA boot loaders are vulnerable to Windows 8.x or Windows 10: write accesses of Windows can confuse the factory bootloader and make the debug firmware and bootloader useless. In this post I show how to recover the bootloader using MCUXpresso IDE and the P&E Universal Multilink.
Using P&E Multilink Universal to restore the OpenSDA Bootloader on NXP FRDM-K22F Board
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 :-(.
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:
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.
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:
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:
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
And as with everything, there are pros and cons of that approach.
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.
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:
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 🙂
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:
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.
During Embedded World 2017 in Nürnberg I was lucky to get a handful LPC800-DIP boards. To get all students who were lucky to get one, here is a tutorial to make that very exciting ‘blinky’ application on that board: