One of the biggest road blocks (beside of closed source) using the BLE (Bluetooth Low Energy) stack from NXP is that it requires expensive tools to compile and build the stack. The good news is that I have now the NXP BLE stack for the Mikroelektronika Hexiwear ported to Eclipse and GNU gcc build tools for ARM 🙂
NXP BLE Stack in Eclipse
A new McuOnEclipse components release was long overdue, so I’m pleased to announce that a new drop is available with the following major changes:
SourceForge
As a standard procedure, I add some console functionality to my embedded applications. That way I have a command line interface and can inspect and influence the target system. One interesting hardware feature of ARM Cortex-M is Single Wire Output (SWO): it allows to send out data (e.g. strings) over up to 32 different stimulus ports, over a single wire.
swo-pin-on-arm-debug-header
From time to time I face some problems which are really hard to find. Mostly these kind of bugs are very timing sensitive and depend on interrupt execution order. Maybe a dangling pointer is overwriting memory, code is running wild, or some functions are not reentrant as they should be. For these kind of bugs, good tools are worth their weight in gold. The Percepio FreeRTOS+Trace and the Segger SystemView have helped me many times to narrow down such kind problems in my applications. Another ultimate tools is hardware trace: Now I have a Segger J-Trace Pro for ARM Cortex-M in my arsenal of bug extinguishing weapons on my desk:
Dear bugs, look what I have on my desk. Your hiding time is over! 🙂
tracing-cortex-m4-with-j-trace
Playing with RFID and NFC is definitely fun :-), and they are everywhere! For a research project I’m exploring different RFID tags and solutions. I several types around for a long time, but never found the time to actually work on it, so last nightI thought I give it a try, and I have it working with GNU ARM and Eclipse, powered by the NXP FRDM-K64F board 🙂
NXP NFC PN7120S with a FRDM-K64F Board
This tutorial goes through the steps how to create a blinking LED application, using Kinetis SDK and Processor Expert, using the TWR-KL43Z48M board from Freescale (now NXP):
twr-kl43z48m
In “ARM Cortex-M, Interrupts and FreeRTOS: Part 1” I started with the ARM Cortex-M interrupt system. Because the ARM implementation cann be very confusing, I confused myself and had to fix and extend the description in Part 1 :-). Thank for all the feedback and comments!
Originally I wanted to cover FreeRTOS in Part 2. Based on the questions and discussions in Part 1 I thought it might be a good idea to provide visual examples.
NXP KV58F ARM Cortex-M7
I kind of hoped that after “Why I don’t like printf()” and all my other articles about printf and semihosting, that topic would be 200% handled and I won’t have to deal with any more. Well, I was wrong and underestimated how the Kinetis SDK is interfering with semihosting. And I underestimated how many of my readers are still using semihosting (even as there are other and better alternatives), so I keep getting questions and requests for help. That’s ok, and I hope I can help :-).
So here is yet again another post about how to turn on semihosting with Eclipse, GNU ARM Embedded and the Kinetis SDK v2.0. This time with the FRDM-K64F board:
FRDM-K64F Board
Smartwatches are around for a while now. To me it is still questionable how useful the ‘big’ ones for iOS and Android are. But there are definitely the crowd funded smartwatch projects which caught my attention. Maybe it is about the ‘do-anything’ with connectivity? One of these gadgets is Hexiwear: a hackable open source device
Hexiwear Device
While it *could* be a kind of smartwatch, the value of this thing is more that it includes a plethora of sensors with two microcontroller, and I can use Eclipse with GNU tools to build my firmware :-).
Alert: Hackster.io is giving away 100 Hexiwears, but you need to hurry up (submission until July 15th 2016)!
Breakout boards are great: they allow me to explore functions quickly, without to build my custom board: all what I need is some wires and ideally a bread board.
Adadfruit MicroSD Card Breakout Board
NXP has released their Kernel Awareness for FreeRTOS in Eclipse (Kinetis Design Studio):
FreeRTOS Kernel Awareness in Kinetis Design Studio
Sometimes things don’t go well, especially with bringing up a new board design. I always sweat blood that first minute when I try to connect with the debugger to a new design: Will it work? After the optical inspection, performing electrical tests (no shortcuts? voltage levels ok?) the inflection point is when I’m connecting the first time with the debugger to the new board: either it will properly connect and program the device (hurrah!) or it will fail and potentially difficult hours of investigations have to follow.
First PCB under Debug
More and more of my students are using Microsoft Windows 10 machines, and my computer has been upgraded to Windows 10 a couple of week ago too. From my work and experience, a new operating system causes always some challenges, and Windows 10 is no difference. And no, this is not about Microsoft vs. Apple vs. Linux, this post is about addressing a potential and painful problem which I have observed with Windows 10 machines, and to my understanding it could happen with any other operating system too. The problem is that somehow on several student machines the bootloader and OpenSDA application on their FRDM boards did not work any more.
FRDM-K64F (top) programming the OpenSDA Bootloader (bottom)
SourceForge
A new release is available on SourceForge, with the following main changes:
A bootloader shall be small and concise. I very much like bootloaders which do not need a ‘special’ program on the host, so I prefer a simple terminal for this. While porting my serial bootloader to the NXP FRDM-K64F board, I have found RealTerm which offers a lot of cool features:
RealTerm
3.5″ Diskette Drives are not widely used any more: CDs, DVDs, memory/thumb drives and downloads from the web are the usual distribution method these days for software. Back a few years ago, software was distributed on one or many 3.5″ diskettes, and even before that time on 5 1/4″ floppy disk drives. So what to do with all these not-used-anymore hardware? Play music with it 🙂
Floppy Music
My wife tells me that I have too many boards on my desk. That is only *partially* correct: there are many, but not *too* many. But I’m working on too many tasks, but that’s a different aspect :-). I’m using more and more the Kinetis SDK V2.0, and as a result of this I have multiple SDKs installed on my machine. Because with the SDK V2.0 I get a download for each device/board installed (see “First NXP Kinetis SDK Release: SDK V2.0 with Online On-Demand Package Builder“). So my list of SDK folders is growing, as shown with the ‘New SDK 2.x’ wizard in Kinetis Design Studio:
Multiple Kinetis SDKs
The same time, the amount of free disk space is reducing. What if I could combine all these SDK’s?
One goal of this blog is to inspire engineers, in one way or another. And when I get reports back that things were useful, I like to share it :-).
So here is something what a team of young undergraduates (Przemyslaw Brudny, Marek Ulita, Maciej Olejnik) did for theirs Master Thesis work at the Politechnika Wroclawska, Poland: a very cool flying machine controlled by two Kinetis K66, having many sensors (on own designed boards) with a custom debug/programmer board similar to the tinyK20, developed with the NXP Kinetis Design Studio:
UAV (Source: Thesis of Przemyslaw Brudny)
“Learning-by-doing” is one of the core principles of my embedded systems and robotics course at the Lucerne University. For this the students apply what they learned using a robotics platform. In earlier semesters we did a Sumo battle at the end. This time the challenge was to build a remote controller plus to add the ability to explore and solve a line maze:
maze solving robots
