In my classes I’m mainly using the Freescale FRDM-KL25Z board, as it provides the best value for the money, and 128 kByte FLASH with 16 kByte of RAM is enough for many smaller projects. I do have as well the FRDM-KL02Z Board (32 KByte FLASH, 4 KByte of RAM) which is an inexpensive board to evaluate the smaller KL02Z microcontroller. Because someone reported a problem not being able to use the UART over OpenSDA/USB-to-CDC bridge, I have created a demo project which communicates with a console on the host.
Tag Archives: freedom board
Sensirion SHT11 Temperature and Humidity Sensor on a MikroElektronika Click Board
In one of my earlier posts (“Using the DHT11/DHT22 Temperature/Humidity Sensor with a FRDM Board“) I’m using the DHT11/DHT22 temperature/humidity sensors with the FRDM-KL25Z board. These sensors are very inexpensive, but have limited measurement range and accuracy. As pointed out by a reader of that article, Sensirion (a Swiss company :-)) has good sensors too, and I decided I would like to try the SHT11 sensor:
- 0-100% Relative Humidity
- +/- 3% Relative Humidity accuracy
- -40 – +125°C
- 2.4 – 5.5V supply voltage
Poor Man’s Trace: Free-of-Charge Function Entry/Exit Trace with GNU Tools
There are cases where my application runs find for days, weeks or even months, but then from time to time there is an application crash. Yes, the watchdog will recover it, but still it would be good to know what happened? One solution would be to hook up a trace probe (like the one I have described in this post: “First Steps with the P&E Tracelink“). But having such a trace probe attached all the time is first not cheap and second not always possible. So what if the application would leave ‘breadcrumbs’ behind which would tell me the flow of the program leading to the problem? I have found a functionality in the GNU tools which seems not be widely known or use, but is incredibly helpful in such cases.
So what if I could get a log like this telling me which functions get called by whom?
{ 00000E88->00000DA0 ???->DEMO_Init
} 00000E88<-00000DA0 ???<-DEMO_Init
{ 00000E8C->00000D40 ???->DEMO_Run
{ 00000D62->00000CE8 DEMO_Run:0x0022->decide
{ 00000D0E->00000C60 decide:0x0026->calcValue
} 00000D0E<-00000C60 decide:0x0026<-calcValue
{ 00000D16->00000CA0 decide:0x002E->getValue
{ 00000CC6->00000C60 getValue:0x0026->calcValue
} 00000CC6<-00000C60 getValue:0x0026<-calcValue
} 00000D16<-00000CA0 decide:0x002E<-getValue
} 00000D62<-00000CE8 DEMO_Run:0x0022<-decide
{ 00000D62->00000CE8 DEMO_Run:0x0022->decide
Using the DHT11/DHT22 Temperature/Humidity Sensor with a FRDM Board
For a home automation project I need to know the room temperature and humidity percentage of the room air. Adafruit has an inexpensive DHT11 sensor from http://www.aosong.com which I decided to use for that project.
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Altium File for Freescale FRDM-K25Z Board
If you are designing your own board for the Freescale FRDM boards, then having the matching PCB design files is a good thing to have. I have posted this week an Altium contribution on GitHub for the FRDM headers (see “FRDM-KL25Z Arduino Headers with Altium“). And here there is yet another contribution I received from [Darren]: the FRDM-KL25Z board in Altium :-):
Command Line Programming and Debugging with GDB
Eclipse with GDB is great: it comes with a graphical front end for debugging. But sometimes it is all about to download a program. Is it really necessary to launch an IDE like Eclipse to program or quickly debug a board? With the GNU Debugger (GDB), the answer is ‘no’: GDB comes with a command line debugger which is designed exactly for this: providing a command line interface for programming/downloading and debugging, bypassing any GUI (Graphical User Interface).
OpenOCD/CMSIS-DAP Debugging with Eclipse and without an IDE
OpenOCD is an open source and free-of-charge debugging solution, which is a great option here at the University of Lucerne, as students do not need to buy an expensive debugging probe. Still, I recommend to buy professional probes like the P&E or Segger ones, as they are worth every (Euro) cent. But for a ‘zero’ budget, OpenOCD with CMSIS-DAP is something to consider. And with Kinetis Design Studio using the GNU ARM Eclipse Plugins, OpenOCD is not that hard to be used. And because both Freescale and GNU ARM Eclipse offer OpenOCD Windows binaries, that connection method is in the reach of Windows users too.
eWheel Velo Bling-Bling Freescale Project
So here is a really, really cool project: eWheel Velo Bling-Bling:
USB with the Freescale FRDM-K22F Board
The FRDM-K22F is one of the latest members of the Freedom board families: 512 KByte Flash, 128 KB RAM and the usual Freedom board components on it. Unfortunately, Freescale decided not to populate the micro-SD card connector on the board, so from this perspective the FRDM-K64F is more value for the money. But the board has USB, so this makes it still interesting. And this is what this post is about: Adding USB to the FRDM-K22F board in a few minutes…
Infotronic WS2014 Sumo Robots are Ready!
The Sumo robots are ready to battle today!







