How to use 15 inch touchscreens

Instructions on the usage of the 15.6 inch SAW touchscreen (LCD-15.6TS) under Debian.

This guide is tested with the LCD-15.6TS (with ETT5003U controller), distributed by Olimex LTD. The setup included LCD-OLinuXino-15.6-FHD and A20-OLinuXino-MICRO.

Important: for the hardware connection you would need to provide 12V to the controller via the touchscreen display using the 4-pin molex connector (yellow wire = 12V input; black wires = GND). A free USB port is also required. The powering to the touchscreen is deliver through a standard 4-pin molex connector.

After all hardware connections are established to get the touchscreen working under the official Linux image do the following:

1. Make sure the USB connection between the display and the board is established before powering the board. If it was connected already reboot the board.

2. Identify the event number of the USB connection of the touschreen. You might plug-unplug the USB connection of the touchscreen to get the proper event number in the console (or use command dmesg | grep ETwo). It is usually /dev/input/eventX or /dev/inputY (listed as "USB HID v1.10 Mouse").

3. Create a new 20-ts.conf file or add a new section in the 20-ts.conf file (remember to replace the USB event number with the number you got in point 1, we have used event2 as example)

The file location is: /usr/share/X11/xorg.conf.d/20-ts.conf

The file should contain the following:

Section "InputClass"
 Identifier "ETwo TouchScreen"
 MatchDevicePath "/dev/input/event2"
 MatchProduct "ETwoTouch Corp. ETwo TouchScreen"
 Driver "tslib"
 Option "ScreenNumber" "0"
 Option "Rotate" "NONE"
 Option "Width" "1920"
 Option "Height" "1080"
 Option "SendCoreEvents" "yes"
 Option "Type" "touchscreen"
EndSection

Remember to replace the event2 number with the number you got in point 1. The configuration is suitable for the FullHD 15.6 inch display. If you are using the 1366x768 (HD-ready) display replace the driver option defaults with "Width" "1366" and "Height" "768".

4. Create a new environment file or edit the environment file (again we have used event2 as our USB event, remember to replace it with the number of event you get in point 1.)

The file is typically: /etc/environment - however it might be different in your board.

TSLIB_TSEVENTTYPE=raw
TSLIB_CONSOLEDEVICE=none
TSLIB_FBDEVICE=/dev/fb0
TSLIB_TSDEVICE=/dev/input/event2
TSLIB_CALIBFILE=/etc/pointercal
TSLIB_CONFFILE=/usr/etc/ts.conf
TSLIB_PLUGINDIR=/usr/lib/ts

Again remember to replace the event2 number with the number you got in point 1.

5. Calibrate the display like root user

ts_calibrate

6. Make sure that you have permissions to start the GUI as another user. Execute:

dpkg-reconfigure x11-common

A menu would pop-up - select "Anybody"!

7. Add the following 2 lines at the end of /root/.bashrc file:

service slim stop
su - olimex -c startx &

8. Reboot the board

reboot

If after reboot the touchscreen works only in a small area - you might want to link the files used by LXDE manually. The files generated by the calibration tool are located in /etc, but LXDE looks for files in /usr/etc/ - make sure that the files generated in /etc folder are the ones used by LXDE. You might need to delete or rename the files in /usr/etc/ and then either copy paste the similar files from /etc or place symlinks to them.

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