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Fixing the rising edge of a 68HC11 output signal

Hardware or software problem? That's the question when your embedded board does not work as expected. Spotting the issue can be a challenge.

The article Fixing the rising edge of a 68HC11 output signal explains the hardware issue that I had, how I investigated it and finally solve the software issue which was the origin of the problem.

Fast and simple insert code into crt0.s


Some time ago there was a question of the sort, "How do I make my own crt0.o file". Then the buzz started, and everyone was talking about how to do these things, including relocating RAM and other hardware configuration.

It seemed overly dificult to worry about things like finding the original crt0.s file (I've only found it burried in the GCC source code), and taking chances of changing too much so it didn't properly initialize RAM and such. Well, I have a solution where all I do is insert my startup code in a specific slot within the default crt0.s without having to edit that file!

What packages for the GNU development chain?

Answer the poll What kind of packages are you the most interested in for the GNU development chain?
and tell what is your prefered distribution.

meaning of blogs

I have wondered a while back what people were supposed to do with blogs. I had read that the name came from "Weblogs", which basically tells all that it is. In the past, I often had misc files where I log ideas or events for later referral. That's what a blog is. The only qestion I had then was; What happens after I start writing blogs?

Yesterday I found good beginner info about blogs and finaly decided to start my blog here.

The idea then is that if we all are blogging what we do with GCC, HC11/HC12, and implementation ideas, together we make a world of difference.

Optimizing global variable accesses by using direct addressing mode

The 68HC11 and 68HC12 micro-controllers support a direct addressing mode that gives access to the lower 256 bytes of the address space. This addressing mode is sometimes called page0 addressing mode. It is optimized to produce short instructions in most cases: it only requires one byte to represent the address instead of two bytes for the extended address mode. The page0 addressing mode as well as the extended addressing mode are used in general to access global variables. The discussion explains how you can tune your applications to use this direct addressing mode.

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