Debugging ARM Cortex-M0+ Hard Fault with MTB Trace

And here it is again: a Hard Fault exception raised by the ARM Cortex-M0+ on my Freedom board:

Hard Fault in Debug View

Hard Fault in Debug View

A reason for hard faults are for example dereferencing a NULL pointer. The issue with the ARM Cortex hard fault exception stack is: it is not easy to find out where in the code the problem is.I have created a Processor Expert component to help me to find the location of such an exception. With the Eclipse based CodeWarrior for MCU10.3 there is another way: Trace with the MTB (Micro Trace Buffer)!

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Reducing the build time with gcc for ARM and CodeWarrior

Eclipse based CodeWarrior for MCU10.3 comes with gcc build tools for Kinetis/ARM cores. While it features the parallel build make, I noticed that especially for larger projects build times are not as fast as it should be. The good news is: I was able to cut down my build time to less than half with a simple change :-).

When I looked at the output folder where all the object and make files are stored by Eclipse, I noticed that it has as well the listing files generated:

Listing Files in output folder

Listing Files in output folder

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Resolving Processor Expert Bogus Errors

Some times, especially after making some clock/timing changes in Processor Expert, I have an error showing up in the Processor Expert components:

Processor Expert Components with Errors

Processor Expert Components with Errors

Many times Processor Expert is right. But not always: It is possible that Processor Expert is stuck on the error, and there seems no way out. But there is a trick to resolve it….

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McuOnEclipse goes Git

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

GitHub Bootcamp: 4 simple steps to git

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Free Static Code Analysis with Eclipse

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

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.

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The Freedom Robot

I have the Arduino Motor Shield working, the Ultrasonic module is pinging around, Christmas brought some small DC toy motors, and a bag of plastic gears is on my desk. All the good ingredients for a small robot: the Freedom Robot!

❗ Warning: Multiple Coke bottles have  been destroyed, and a FRDM box got hurt during his experiment! 😯 Do not try yourself if you cannot handle it.:-)

Smile

Smile

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Tutorial: Ultrasonic Ranging with the Freedom Board

Question: What makes 8 times ‘beep’, but I cannot hear it?

Answer: My ultrasonic range finder 🙂

FRDM-KL25Z with HC-SR04

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.

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2012 in review: Happy New Year, and thanks for reading!

Thanks for reading and following this blog, for all the comments and suggestions and the encouraging feedback!  And many new exciting projects are waiting for 2013 :-).

Happy New Year!
Erich

PS: If you believe in statistics and numbers, then here is something for you: The WordPress.com stats helper monkeys prepared a 2012 annual report for this blog.

Here’s an excerpt:

19,000 people fit into the new Barclays Center to see Jay-Z perform. This blog was viewed about 110,000 times in 2012. If it were a concert at the Barclays Center, it would take about 6 sold-out performances for that many people to see it.

Click here to see the complete report.

A new Freedom Board: FRDM-KL05Z

Christmas and New Year time is great: Gifts and time to work on my home projects. But this post is not about one gift I have organized for myself: a Raspberry Pi ;-)). No, this post is about a gift I have received from Freescale: a *new* Freedom board, the FRDM-KL05Z :-).

FRDM-KL05Z Board and Box

FRDM-KL05Z Board and Box

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PWM and Shell for a LED

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

LED Properties

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