In this chapter I want to discribe the history of this mini-mini-howto.
In 1995 I was searching for an expansion board for my home-PC. It was a PC-AT with 386 CPU and at that time I was programming with clipper. I wanted to read some digital and analog input and I thought that I don't want a board in my PC. I was searching for an external solutions.
I found the velleman K8000 board in an electronic shop. There was a source code for the driver available. I compiled this code with borland-C compiler and linked it together with my Clipper application. This program is running since Summer 1995 an doing some watching of my oil-heating at home.
Today this old machine is the last DOS-based machine at home. All other PCs are running with Linux. I searched through the web a lot of hours and found only the i2c-velleman.c Kernel-driver in the kernel-tree. But I couldn't find any examples, how to connect from a small C-program to the K8000 board. So I decided, to try to hack it by myself. After the program(s) was(were) running I wrote this small HOWTO.
However, if you find I could help you learning howto connect from C to your Velleman K8000 board, feel free to send me a short message. I would be happy to hear from you - I am sure thare there are some other K8000 user out there :-))
In a discussion with hihihi <hihihi@wanadoo.nl> I found out that there also exists a velleman-library called libk8000. This HOWTO does not support this library-solution. Here I discribe the connection via kernel-drivers. At this point I want to thank hihihi <hihihi@wanadoo.nl> for his hints and for testing this HOWTO.
When you finished soldering your K8000, you should switch the two DIP-Switches to the off position.
You should prepare your system by running the following script (I stored it under the name "velle")
#! /bin/bash
echo free the Parport ...
/sbin/rmmod lp
/sbin/rmmod parport_pc
/sbin/rmmod vmppuser
/sbin/rmmod parport
echo i2c Treiber laden ...
/sbin/modprobe i2c-velleman
/sbin/modprobe i2c-dev
echo create the device-handle and free it for all users
cd /dev
rm velleman
# The following part was written by hihihi#wanadoo.nl
# Jan 31 2002
# A variation on the ./velle script of Heimo Schoen.
Filename=/proc/bus/i2c
line="not empty yet"
echo
echo " Look for I2C devices in /proc/bus/i2c :"
echo
while [ "$line" != "" ]
do
read line
echo " " $line
if echo "$line" | grep -q "Velleman K8000"
then
K8000Entry=$line
fi
done <"$Filename"
echo
echo " Found a Velleman K8000 entry:" $K8000Entry
echo
K8000Nod=${K8000Entry#i2c-}
echo $K8000Nod
K8000Nod=`expr match "$K8000Nod" '\([0-9]*[0-9]\)'`
echo $K8000Nod
mknod velleman c 89 $K8000Nod
chmod a+rw velleman
echo Etwas auf die K8000 jagen ...
echo hallo > /dev/velleman
You can download this script here