HidTouch User Manual, and setup for an ET&T TC4UM Touch screen

by David SPORN

(sorry for the poor quality, I was in a hurry. I hope I will do better next time)

Content

[1] HidTouch User Manual, and setup for an ET&T TC4UM Touch screen

[1.1] Licence

[1.2] Known bug

[1.3] Environnement prerequisites

[1.4] udev rule for the TC4UM TouchScreen

[1.5] Installing

[1.5.1] ./configure --prefix=/usr

[1.5.2] make

[1.5.3] sudo make install

[1.6] One more thing : calibrating and finding other parameters

[1.7] Setting up xorg

Licence

This program is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation; either version 3 of the License, or (at your option) any later version.

This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details.

You should have received a copy of the GNU General Public License along with this program; if not, write to the Free Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA

Known bug

The button event does not have an effect, despite the driver send button events.
There is no error correction to compute the location of the cursor

Environnement prerequisites

I use Ubuntu 8.04, so the following directive must be adapted to your environnement.

In order to be able to compile the driver, the following packages must be present :

build-essential
autotools-dev
autoconf
automake
xserver-xorg-dev
pkg-config
libtool

If this is not enough, the following packages might be mandatory (please send me confirmation about that) :

libX11-dev
libxext-dev
libxtst-dev

udev rule for the TC4UM TouchScreen

SUBSYSTEM=="usb", ATTRS{idVendor}=="0664", ATTRS{idProduct}=="0306", SYMLINK+="ETandT-$attr{product}"

Installing

Extract the files from the archive, then invoke the following command :

./configure --prefix=/usr

The prefix parameter is set to "/usr" so that make install put the driver in the correct location in the case of a standard installation of xorg in /usr.

make

Normally there must be no problem.

sudo make install

Sudo is mandatory. After that the module is in the right place, ready to be used

One more thing : calibrating and finding other parameters

In a temp directory, create a file named "test.c" with the following content :

#include <stdlib.h>

#include <stdio.h>

#include <sys/ioctl.h>

#include <sys/types.h>

#include <sys/stat.h>

#include <asm/types.h>

#include <fcntl.h>

#include <unistd.h>

#include <linux/hiddev.h>

int main( int argc, char *argv[] ) {

int i;

struct hiddev_event packet;

int fd = -1;

/* requires a file descriptor, so we check we got one, and then open it */

if (argc != 2)

{

fprintf(stderr, "usage: %s hiddevice - probably /dev/usb/hiddev0\n", argv[0]);

exit(1);

}

fd = open(argv[1], O_RDONLY | O_NONBLOCK);

if ((fd = open(argv[1], O_RDONLY)) < 0) {

perror("hiddev open");

exit(1);

}

int data_read ;

unsigned char data ;

for(;;)

{

for(i=0; i<6; i++) {*/

data_read = read(fd, &packet, sizeof(packet)) ;

if (data_read < 0)

{

printf("no data\n");

sleep(50);

break ;

}

printf("%x\t%i\t", packet.hid, packet.value);

}

printf("\n");*/

}

close(fd);

return 0;

}

Compile with gcc -g -Wall -o dumpDevice dumpDevice.c

Then invoke with :

sudo ./dumpDeviceAsync /dev/your_device

Touch the screen and identify the value of interest : which code correspond to the pressure, x position and y position.

For example I obtain the following with the ET&T TC4UM:

d0042 1 d0045 0 d0045 0 d0045 0 10030 1275 10031 1040

d0042 1 d0045 0 d0045 0 d0045 0 10030 1272 10031 1039

d0042 0 d0045 0 d0045 0 d0045 0 10030 1272 10031 1039

d0042 1 d0045 0 d0045 0 d0045 0 10030 1072 10031 1228

Moving my stylus, I find the parameter for the driver (opcode parameter value are converted to decimal values) :

Option "PacketCount" "6"

Option "OpcodePressure" "852034" #d0042

Option "OpcodeX" "65584" #10030

Option "OpcodeY" "65585" #10031

Option "MinX" "89"

Option "MinY" "174"

Option "MaxX" "1846"

Option "MaxY" "1696"

Setting up xorg

Edit your xorg.conf to add the device. Here is my conf :

Section "InputDevice"

Identifier "ETT Touch Panel"

Driver "hidtouch"

Option "SendCoreEvents"

Option "ReportingMode" "Raw"

Option "Device" "/dev/ETandT-TC4UM"

Option "PacketCount" "6"

Option "OpcodePressure" "852034"

Option "OpcodeX" "65584"

Option "OpcodeY" "65585"

Option "MinX" "89"

Option "MinY" "174"

Option "MaxX" "1846"

Option "MaxY" "1696"

EndSection

...

Section "ServerLayout"

...

InputDevice "ETT Touch Panel" "SendCoreEvents"

...

EndSection

Restart Xorg (Ctrl + Alt + BackSpace) and now the mouse cursor follows your finger and your stylus.