Category Archives: CPU’s

Debugging ARM Cortex-M0+ Hard Fault with MTB Trace

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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

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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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The Freedom Robot

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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

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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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A new Freedom Board: FRDM-KL05Z

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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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A Processor Expert Component to Help with Hard Faults

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Ahrg! Again my ARM application crashed somewhere and I ended up in a HardFault exception :-(. In my earlier post I used a handler to get information from the processor what happened. But it is painful to add this handler again and again. So I decided to make things easier for me: with a special HardFault Processor Expert component :-).

After adding this HardFault component to my project, it automatically adds an entry to the vector table. So no manual steps are needed: having the component in the project and enabled will do the needed steps.

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Migrating Kinetis-L Projects from Beta to Final MCU 10.3

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I have successfully used CodeWarrior for MCU10.3 beta version for many projects. With the advent of the final CodeWarrior for MCU10.3, I want to migrate my existing projects to the new and final version. First: my existing projects work as well in the final version, which is good news. But there are two things to change to take advantage of the final 10.3:

  1. Linker file memory split
  2. ARM Micro Trace Buffer (MTB) support

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LED’s for Kinetis, simplified

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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.

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HD44780 2×16 Character Display for Kinetis and Freedom Board

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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

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 🙂

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Reducing Code Size with gcc and EWL

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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

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