When I have asked by a student last year if I’m uing Git, I said “Git what?”. Yep, a shame I did not know what Git was a this time. But it is never to late to learn new things.
I was coming from CVS, moved to the successor of it (SVN) and was happy with it. Especially with having a local SVN server and repository, that was (and still is) a great thing. But to truely collaborate with a worldwide community, it is time to use something different: Git.
GitHub Bootcamp: 4 simple steps to git
I know for myself: the earlier I’m able to fix a bug, the better. So I’m always grateful for things which help me to find issues in my sources as early in the development process as possible. Eclipse and CodeWarrior already help me to find syntax errors in my code while I’m typing:
Eclipse highlighting syntax error
With the built-in syntax checker of Eclipse, this helps me many times to get things right without the need to build my code with the compiler. But when I’m able to compile successfully my code, this does not mean it is without bugs. It would be good to catch as many errors *before* downloading and running it on the target.
Question: What makes 8 times ‘beep’, but I cannot hear it?
Answer: My ultrasonic range finder 🙂
FRDM-KL25Z with HC-SR04
What I have added to my FRDM-KL25Z board is an ultrasonic distance sensor, measuring distances up to 4 meters.
Controlling a LED is a great starter for any embedded project: simple and you immediately get feedback if it works :-). Even better: as driving a LED is not different from working with another digital I/O or controlling a solenoid, the ‘LED’ concept and driver is very universal. I recently have simplified my Processor Expert LED component, so it might be a good time to add some more functionality again ;-). Let’s add support for PWM, and adding a shell interface on top of it. That way the LED is dimmable, plus I can do everything with a command interface as well:
LED Properties
With Processor Expert projects, I have a nice overview of pins used in my application:
Processor View
While that Processor View is nice, I want a list of pins and signals too:
Sometimes it takes a while until things get better. Same thing applies to software: from time to time a refactoring and simplification makes sense. Especially if the underlying technology has been improved. With CodeWarrior for MCU10.3 available, it is time to refactor the LED component.
The CSI is one of my favorite crime drama television series: not because it reflects the true reality, but because it is fun watching how they always find new ways how to investigate a crime scene with ‘close to reality’ tools. Real CSI is different: you only do a small part of the investigation chain. As for myself, I’m engaged in a research project at the university to develop hardware and software for crime scene investigation :-).
One area of that research project is to retrieve and data from credit card (ATM) skimming devices: these are devices are attached or inserted into credit or debit card machines and ‘skim’ the card information and the PIN code used. With that information, it is possible to clone a credit card for credit card fraud. Such devices are a big problem, and newer devices are very hard to spot. Simply ‘google’ for pictures for “skimming device” and you will get an idea of the diversity and madness of such devices :-(.
Microscopic investigation of skimming device
In my earlier Nokia LCD post I described a ‘free of charge’ way to add a LCD display to my FRDM-KL25Z board. If that Nokia display is not available, or an alphanumeric display is enough, then the Hitachi HD44780 display is a low cost option as well.
The HD44780 (or compatible) display is one of the most common displays available. And they usually conly costs around $10 or less. I have used a ‘blue’ 3.3V version of such a display already in my lectures with a Freescale S08 microcontroller. So I thought it would be nice to port the driver to the Kinetis and the KL25Z on it.
LCD Boards with FRDM-KL25Z
A recent post of TKJ Electronics about such a really inexpensive (only $5) HD44780 display caught my attention. And finally I had two of such TKJ displays in my postal mail box yesterday. Time to have some fun on a weekend 🙂
If you have not noticed: the final CodeWarrior for MCU10.3 has been released on the Freescale web :-).
It comes with a few changes compared to the 10.3beta release, and one is about the library configuration. I noticed that new projects created with the wizard are around 4 KByte larger than I expect them to be. For example my rather simple application below uses 8 KByte of code, where my expectation would be in the range of around 4 KByte:
  text     data      bss      dec      hex   filename   8644       24     1108     9776     2630   Freedom_2x16_HTA.elf
The Freedom KL25Z board has a great price of less than $15. Adding a typical LCD usually will add a multiple of that price to the budget. But hey, there is a way to add a LCD to that board at almost no costs! With the idea that I have an old outdated Nokia phone, and the cost of a small capacitor plus some wires are considered as ‘zero’ ;-).
Say Hello from the Freedom Board
MCU on Eclipse 