The latest addition to my set of Arduino shields is a true fun thing: The ElecFreaks.com JoyStick Shield 🙂
ElecFreaks.com Joystick Board with FRDM-KL25Z and nRF24L01+
JoyStick Shield with the FRDM Board
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Tag Archives: software
FRDM with Arduino Ethernet Shield R3, Part 4: MinIni
I admit: my Ethernet Shield project got stuck because of too many urgent other priorities. I was not happy with the way the project was using configuration data from FLASH memory: I have now multiple ethernet shields in use, and configuring the IP address for each shield is a pain. I have not got DHCP working (yet), so why not using the SD card on the shield for configuration data? And right on time I received a tip from Marc about MinIni: perfect, exactly what I need!
Ethernet Shield with SD card
GNU Linker, can you NOT Initialize my Variable?
my students sometimes are afraid to ask questions, although I urge them ask any question. In my opinion there are no ‘dumb’ questions: only questioning things let us think and learn new things. I see that many readers of this blog are *not* afraid to comment or ask questions. The WordPress statistics shows 5’687 questions/comments for this blog (thank you all!), and the spam filter protected me from 202,341 items (ok, these *are* dumb) :-).
The ‘question of the week’ comes from Andy. That question caused me some serious head scratching, but the same time I have learned something important and useful for my next project: how to tell the ARM GNU linker *not* to initialize variables?
GNU ARM Embedded Linker Options
Pin Muxing: Using the NMI Pin as GPIO Pin
Many modern microcontroller have a cool feature: Pin Muxing. What it means is that I can ‘mux’ the pins for different purposes: such as I can use a SPI or I2C pin as GPIO (General Purpose Pin) or vice versa. In an ideal world, I would be able to ‘route’ or ‘mux’ pins freely around. In practice these ‘way switches’ are more or less limited.
In “Using the Reset Button on the Freedom Board as User Button” I muxed the FRDM-KL25Z reset pin as GPIO pin. The same approach can be used for muxing the NMI (Non-Maskable Interrupt) pin for the Freescale Kinetis devices. I’m showing it here how to do this with Processor Expert as this allows me to do this with a few mouse clicks.
NMI Pin Used as GPIO Pin
Tutorial: User Interrupts with Processor Expert
I have been asked this question several times:
“How can I define my own interrupt vector with Processor Expert?”
So I think it deserves a short tutorial, if more than one person is asking this ;-).
My user interrupt in the vector table
Processor Expert (Driver Suite/Plugins/KDS) V10.4 with new Component Inspector
There has been a lot of new Freescale releases recently around FTF, and I’m trying to catch up. For me as a Processor Expert Lover, it is good news that there is now the new version 10.4 available. And it comes in different ways:
- Standalone as Driver Suite 10.4 (e.g to be used with IAR or Keil).
- As plugin for existing Eclipse installations (e.g. Kepler)
- Integrated into CodeWarrior for MCU10.6 (which just has been recently released too)
- and in Kinetis Design Studio which just has been announced at FTF.
Microcontrollers Driver Suite v10.4
GNU Additional Tools: Create Flash Image, Print Size and Extended Listing Options
One question I have been asked several times here at FTF:
“How can I create an S19/Motorola S-Record with Eclipse?”
The answer depends on which Eclipse you are using. Actually it depends on which (ARM) build tools plugin you are using, as with Eclipse you have the freedom of choice.
And this is not only about S19/Binary (Flash Image), but covers ‘Extended Listing’ and ‘Print Size’:
Additional Tool Options
Getting Bluetooth Working with JY-MCU BT_BOARD V1.06
For my embedded course at the University of Lucerne of Applied Sciences and Arts I needed more Bluetooth modules for the Zumo/Sumo robots. I run out of stock as the modules are getting popular and are used in many student projects. So I ordered a handful more from DX/DealExtreme of the same HC-06 type/part number I already ordered a while back. I expected that they will work as the modules I had ordered from DX half a year ago. Was that naïve? Probably. Because they did *not* work, and caused me to reverse engineer the modules and to apply a hardware fix to get them working….
Set of JY-MCU Bluetooth Modules
Serial Terminal View with Eclipse Kepler
Nearly all of my projects have built-in command line support: using a serial connection, I can send commands or inspect the system status. For this I have my command line Shell which works over serial-to-Bluetooth, serial-to-USB, USB CDC or with a physical serial (COM) port. But what I need on the host system is a Terminal program: I can use either an external program. There are many ones available (Tera Term, PuTTY, …) where Termite is my favorite one. But it is possible to extend Eclipse so it has its own Terminal view too :-).
Eclipse Terminal View
FreeRTOS, malloc() and SP check with GNU Tools
FreeRTOS has many memory allocation options (see Memory Management) with four ‘schemes’. One of it is the a simple wrapper over the library malloc() and free() routines. I admit, I have not used them, as usually I avoid to include such kind of libraries, as they have their own problems. Anyway, a discussion in the FreeRTOS forum raised my interest: obviously some malloc() implementation (as in the EWL library of CodeWarrior) are making a safety check against the current stack pointer.
MCU on Eclipse 