ring0 » blog

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.

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

tags: n900, debian, wireshark, lua, phonet, isi 2010-08-26 01:10 by sre

In the last days I finally got some bits out of the Nokia N900’s modem on Debian without any properitary tools. For now it’s just the following information:

manufacturer: "Nokia"
model: "Nokia N900"
revision: "V ICPR82_10w08 25-02-10 RX-51 (c) Nokia"

But the most difficult part is probably done. My next plan was to get the modem connect to a mobile network, which requires an unlocked SIM card. Unfortunately ofono does not yet support SIM cards with PINs. Thus I had to find another way to get out how to perform this task.

Another Debian on N900 Update

tags: n900, debian, enlightenment 2010-08-15 17:47 by sre

First of all the Debian on N900 page moved to https://elektranox.org/n900. Now about the recent changes: