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

GNU ARM Embedded Linker Options

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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

NMI Pin Used as GPIO Pin

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Creating New Eclipse Debug Configuration


Eclipse is very powerful. To the point that you can do the same thing in multiple ways. I’m always learning new things, and recently I discovered a new way how to create a new launch or debug configuration.

So far I selected the item (e.g. GDB Hardware Debugging) and used the ‘New’ Icon:

New Debug Configuration with New Icon

New Debug Configuration with New Icon

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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

My user interrupt in the vector table

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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:

Microcontrollers Driver Suite v10.4

Microcontrollers Driver Suite v10.4

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The Zumo Bots at FTF 2014


I should have known it better, and I always teach my students that they should take the environment into account. And you know what? This time it was me who missed following that rule.

But from the beginning: For the Freescale Technology Forum (FTF) I brought 4 different Zumo Robots to show developing with the Freedom board and Processor Expert. Clark (thanks again, Clark!) has built and brought the Sumo Dojo, and I brought the bots:

Zumo Bots at FTF

Four Zumo Bots at FTF

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