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I2C VGA Adapter

tags: debian, i2c, vga, hdmi, dvi, hardware, electronics, logic level converter, linux 2012-07-07 08:41 by sre

For one of my projects I’m making heavy use of I²C devices. For development it would be nice to connect them to my notebook and develop and debug the sourcecode natively.

Luckily I remembered that all common display connection standards (VGA, HDMI, DVI) have an I²C control channel. In the linux kernel these pins are exported as I²C device by the graphic card driver. For example my intel driver exports 8 I²C devices.

So the only hardware needed to use an I²C device on my notebook is a cheap VGA cable. After cutting it in half we have two I²C adapters. I decided to create one cable for 5V I²C devices. This one is already done after cutting the cable in half. I soldered a jumper wire connector on the four needed wires and removed the others.

Debian: Japanese (にほんご) support

tags: debian, input, latex, japanese 2011-11-15 01:11 by sre

I’m currently participate in a Japanese course at my university. Therefore I want to be able to input Japanese characters on my notebook.

To do this it’s enough to simply install the package ibus-anthy, ibus-gtk and ibus-gtk3. Afterwards you can switch between normal input mode and japanese input mode via the keystroke combination CTRL+Space.

But I’m a vim user and found it anoying to remember leaving the Japanese mode before leaving the Edit mode (otherwise vim’s Normal mode won’t work correctly). I want vim to take care of that for me, so I added a small function to my vimrc:

" source: http://d.hatena.ne.jp/fuenor/20110705/1309866529
au InsertLeave * call PyIBusDisable()

function! PyIBusDisable()
python << EOF
import ibus
bus = ibus.Bus()
ic = ibus.InputContext(bus, bus.current_input_contxt())
Last but not least I want LaTeX support. For this two more packages are needed: latex-cjk-japanese and latex-cjk-japanese-wadalab. After installing the packages there’s an UTF-8 example file showing how it works in /usr/share/doc/latex-cjk-common/examples/CJKutf8.tex.gz.

If you hit any errors it may help to remove ~/.texmf-var. Check Debian Bug #406701 to get more details.

google summer of code 2011

tags: gsoc 2011-04-01 00:00 by sre

The list of accapted projects for google summer of code 2011 has been released! Like last year, I will release the list of projects, which caught my eye:

N900 Debian Kernel

tags: n900, linux, kernel, debian, uboot 2010-11-22 22:45 by sre

After lots’s of tries and help from different people I got my own kernel running on the N900, which is based on the Debian kernel package. So far it just offers basic features (e.g. framebuffer, keyboard) and is missing some important ones (e.g. touchscreen).

To test it on your phone you need to do have Debian installed on an µSD card, install uboot on the N900 (as described in Debian on N900: U-Boot) and install the kernel package.

You can fetch the package from http://pkg-n900.alioth.debian.org. I also uploaded the kernel config next to the package, so that you can check if a specific feature is enabled.

I will ask for inclusion into the official package now.

Writing Wireshark Plugins in C

tags: n900, wireshark, phonet, isi, c 2010-10-05 02:38 by sre

After some time writing the phonet dissector for wireshark in lua I noticed the disadvantages:

So I tried the C interface. I found the basic structure for plugins pretty fast in their documentation and thought about some design changes in the plugin: