The Teensy boards are great, but as they are they are not really useful for real development, as they lack proper SWD debugging. In “Modifying the Teensy 3.5 and 3.6 for ARM SWD Debugging” I have found a way to get SWD debugging working, at that time with Kinetis Design Studio and the Segger J-Link. This article is about how debug the Teensy with free MCUXpresso IDE and the $20 NXP LPC-Link2 debug probe:
“Amazon FreeRTOS – IoT operating system for microcontrollers”: The announcement of FreeRTOS V10.0.0 was one of the biggest news last week for me. Not only is there now a Version 10, the bigger news is that FreeRTOS is now part of Amazon. Wow! Now this explains why Richard Barry (the founder behind FreeRTOS) was kind of hiding away for about a year: he joined Amazon as a principal engineer about a year ago. I think we all have to wait and see what it means for FreeRTOS.
The NXP Freedom boards are very popular. Many of them are inexpensive (less than $20), include a debug interface and can be easily extended with extra shields or boards. Especially the FRDM-KL25Z is very popular: I’m getting told because of Processor Expert and tutorials available on web sites like this one ;-).
Unfortunately there are no small or breadboard friendly Kinetis boards available. There is the NXP LPC800-DIP but with no onboard debugger and without Processor Expert support. We have the tinyK20, but projects tend to use more CPU power, FLASH and RAM space than what the tinyK20 board (50 MHz, 128 KByte FLASH, 16 KByte RAM) can provide. So we ended up designing the big brother of the first tinyK20: the tinyK22 with 120 MHz, 512 KByte of FLASH and 128 KByte of RAM.
Back in March 2017, NXP had rolled the MCUXpresso IDE starting with Version 10.0.0. With the intent to unify the SDK, LPCXpresso, CodeWarrior, Kinetis Design Studio and Processor Expert into one unified and integrated set of tools. V10.0.0 was a good start. The MCUXpresso IDE V10.0.2 in July was more of a smaller update, and the Pin and Clock configuration tools were not integrated, no added tool for peripheral configuration.
A week ago the MCUXpresso V10.1.0 has been released which shows where the journey is going: an free-of-charge and code size unlimited Eclipse based integrated set of tools to configure, build and debug Cortex-M (Kinetis, LPC and i.MX RT) microcontroller/processor based applications.
Clock Tool inside MCUXpresso IDE
I have used it for a week, and although many things are still new, I thought I’m able to give an overview about what is new.
I’m using many microcontroller in my projects. And a lot more are available out there in the ecosystem. Like many others, I tend to select what I am familiar with. But is this the correct approach to select the hardware and tools for a next project?
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.
Kinetis Design Studio by default uses an older version of EmbSysRegView. This article explains how to upgrade to the latest and greatest version 0.2.6. And how it is possible to use the latest NXP update for the 0.2.4 version:
Most of the time I’m using a dedicated terminal program like Termite or PuTTY to connect to a board using virtual or non-virtual COM port. Another way is to use the Eclipse built-in Terminal view: that way no extra program is needed to communicate with a real or virtual COM port to my target device:
I’m pleased to announce that a new release of the McuOnEclipse components is available in SourceForge. In this release more ARM Cortex devices/vendors are supported with different SDKs, plus it comes with several FreeRTOS enhancements for debugging highly optimized code.
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.
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:
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 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 🙂
The GNU tools include powerful utilities to collect coverage information. With coverage I know which lines of my code have been executed, which is a very useful test metric. The GNU coverage tools are commonly used for Linux applications. But to my surprise not much for embedded application development, mostly because it requires a few extra steps to have it available? Why not using free and powerful tools for improving software quality? This article explains how to install the GNU gcov tools into the Eclipse IDE.