The concept of Linux (Open Source, broad developer base and broad usage) is a success story. While there is a lot of diversity (and freedom) in the Linux world, Linux is Linux and again Linux :-). And the world has (mostly) standardized on Linux and its variants on the high embedded system side.
“The Linux Foundation Announces Project to Build Real-Time Operating System for Internet of Things Devices. Open source Zephyr™ Project aims to deliver an RTOS; opens call for developers to help advance project for the smallest footprint IoT devices.“
Ζεφυρος (Zephyros) is the Greek good of spring and the west wind. Obviously this inspired the logo for the Zephyr project:
But one issue I have faced several times is that the board works fine while debugging and connected and powered by a host machine, but does not startup sometimes if powered by a battery or started without a debugger attached. I have found that the EzPort on the microcontroller is causing startup issues.
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.
This is the third part about ARM Cortex-M and how the interrupts are used. In Part 1 I discussed the Cortex-M interrupt system and in Part 2 I showed nested interrupt examples. This part is about FreeRTOS and how it uses the Cortex-M interrupt system.
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:
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:
Sometimes it is very convenient to load a new firmware to a board without the need for a hardware debugger. This is usually done with a bootloader. The NXP Freedom and Tower evaluation boards have on-board debug device/microcontroller (OpenSDA) which can load different firmware implementations like CMSIS-DAP/mbed, P&E Multilink or a Segger J-Link OpenSDA applications. Both mbed and P&E implemenations support to program the board with drag&drop: simply send a file to a virtual MSD (Mass Storage Device) to get it programmed. The latest Segger OpenSDA firmware has this ability added now too: Programming the board with a virtual MSD device:
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 🙂
There are plenty of different software packages available for microcontroller these days from all the silicon vendors. Finding a good software package is one challenge, getting what I really need is another one. Freescale is now part of NXP since December 2015, so this is probably the first release of the former Freescale part now as NXP: The NXP Kinetis SDK Version 2.0.
It comes with an interesting distribution way: instead of downloading huge packages with all-and-everything in it, I can build it ‘on demand’ online and get what I need, on demand from a web-based front end:
This tutorial explains how to profile an embedded application (no RTOS needed) on ARM Cortex-M devices with GNU gprof. Additionally I explain the inner workings to generate the data necessary for gprof.
It has been a long time since I wrote my last blog. I really want to apologize to you all for the delay, but I was busy with another project about the competitive analysis of Freescale with our competitors. I hope I can provide you guys later with some important findings from my research.
Well as far as my project for neopixels using FRDM-K64F is concerned, Erich wrote the wonderful tutorial for all of us to turn on the NeoMatrix. I tried my hands on that and I was indeed able to turn on the board but not in the way I wanted it to. 😦 So, it turns out that I got few LEDs turning blue or some turning green. I asked Erich about it and I got to know that it is because I screwed up with the timing signals. I was using an oscilloscope and not a logic analyzer but Erich’s recommendation was to use the Logic Analyzer. This was the result of my experiment following Erich’s tutorials.
This is Part 1 of a Mini Series. Manya has challenged herself to use the Adafruit NeoPixels (WS2812B RBG LEDs) with the Freescale FRDM-K64F board and the Kinetis SDK (see “Let’s play with Freescale FRDM-K64F“). I did a while back that with the FRDM-KL25Z board (see “NeoShield: WS2812 RGB LED Shield with DMA and nRF24L01+“). I used Processor Expert in my project (without the Kinetis SDK), and with this setup it is very easy. However, Manya wanted to do this with the Kinetis SDK and without Processor Expert. No surprise to me, she has found out that this setup with the Kinetis SDK and without the usage of Processor Expert is much more challenging (see “Not done yet!!“). I promised to Manya to give her a helping hand, so here we go! 🙂
Adafruit 8×8 NeoPixel Shield with Freescale FRDM-K64F Board
This blog is a guide on how to setup using the FatFs library included with the Kinetis SDK 1.2.0 using mostly the Processor expert within Eclipse Luna. FatFs is a generic FAT file system module for small embedded systems written by Chan. I prefer to use Processor Expert when possible as this will often generate code that is smaller in size than using the KSDK library files direct. I experienced many gotcha’s and complication setting this up and wanted to share how I finally managed to get it to work.
Hi again to all the amazing readers of this blog! Well guess what, I am still stuck with the programming code of my NeoMatrix Demo. I think it all started with a bad choice of importing the program and libraries from the mbed to KDS. 😦
Well in my last blog I told you about importing the projects and then building them. Well that was what I was trying to do but it turns out that it is not a good idea. I still have a compilation error which is there probably because of a missing assembly. Debugging the code can sometimes be really frustrating for me. 😐 So, I have decided to start from the scratch and write the code in Kinetis Design studio with the help of the Kinetis SDK. There is already the gpio example for FRDM-K64F available under the driver examples folder in KSDK_1.2.0
Getting the hands on an embedded project has always been exciting for me. So, here I am again with my blog trying to provide you with an easy to use guide for the Kinetis Design Studio 3.0.0 (KDS_3.0.0). Well, as you all know I am an intern at Freescale working for the first time on KDS, I will tell you what all we can do to start working on it with a perspective of a novice. But personally I feel KDS is one of the most encouraging IDE you can work on. So how do I start with my code for our NeoMatrix board? I am currently working with one of the demo codes for the NeoMatrix:
So, my first task is to write the code in KDS for the NeoMatrix_Demo. How do I do that? After opening the KDS 3.0.0, I need to go to File and select New and then Kinetis Project. You can see that the New Kinetis Project wizard appears once you click the File>New> Kinetis Project. Type a name and click next.
This link gives me the opportunity to download the very helpful Kinetis Software Development Kit (SDK) along with the Integrated Development Environment which includes the toolchain Kinetis Design Studio. Let us talk a bit about the Kinetis SDK in this blog. So what does Kinetis SDK is responsible for? In simple terms, it is just software framework which helps us in developing applications across all Kinetis Microcontrollers. It is a package of pre-written code that developers can re-use in order to minimize the amount of unique code that they need to develop themselves.