RASP-PiTFT-Touch

Présentation

Crédit: AdaFruit Industries www.adafruit.com

L'écran PiTFT est équipé d'un film résistif, ce qui permet de simuler le fonctionnement de la souris en touchant l'écran.

Il convient néanmoins d'installer le support logiciel nécessaire (pour bouger le pointeur de souris) et d'effectuer une calibration.

Configurer la partie tactile

Now that the screen is working nicely, we'll take care of the touchscreen. There's just a bit of calibration to do, but it isn't hard at all.

Before we start, we'll make a udev rule for the touchscreen. That's because the eventX name of the device will change a lot and its annoying to figure out what its called depending on whether you have a keyboard or other mouse installed.

Run

sudo nano /etc/udev/rules.d/95-stmpe.rules

to create a new udev file and copy & paste the following line in:

SUBSYSTEM=="input", ATTRS{name}=="stmpe-ts", ENV{DEVNAME}=="*event*", SYMLINK+="input/touchscreen" 

Crédit: AdaFruit Industries www.adafruit.com

Remove and re-install the touchscreen with

sudo rmmod stmpe_ts; sudo modprobe stmpe_ts

Then type ls -l /dev/input touchscreen

It should point to eventX where X is some number, that number will be different on different setups since other keyboards/mice/USB devices will take up an event slot

Crédit: AdaFruit Industries www.adafruit.com

There are some tools we can use to calibrate & debug the touchscreen. Install the "event test" and "touchscreen library" packages with

sudo apt-get install evtest tslib libts-bin

Crédit: AdaFruit Industries www.adafruit.com

Now you can use some tools such as sudo evtest /dev/input/touchscreen which will let you see touchscreen events in real time, press on the touchscreen to see the reports.

Crédit: AdaFruit Industries www.adafruit.com

Crédit: AdaFruit Industries www.adafruit.com

OK lets start the calibration process! You will want to calibrate the screen once but shouldn't have to do it more than that. We'll begin by calibrating on the command line by running

sudo TSLIB_FBDEVICE=/dev/fb1 TSLIB_TSDEVICE=/dev/input/touchscreen ts_calibrate

follow the directions on the screen, touching each point. Using a stylus is suggested so you get a precise touch. Don't use something metal, plastic only!

Crédit: AdaFruit Industries www.adafruit.com

Crédit: AdaFruit Industries www.adafruit.com

Next you can run sudo TSLIB_FBDEVICE=/dev/fb1 TSLIB_TSDEVICE=/dev/input/touchscreen ts_test which will let you draw-test the touch screen. Go back and re-calibrate if you feel the screen isn't precise enough!

Crédit: AdaFruit Industries www.adafruit.com

Calibration X

You can also calibrate the X input system but you have to use a different program called xinput_calibrator

You can do this if the calibration on the screen isnt to your liking or any time you change the rotate=XX module settings for the screen. Since the screen and touch driver are completely separated, the touchscreen doesn't auto-rotate

Normally you'd have to compile it but we have a ready to go package for you so run:

wget http://adafruit-download.s3.amazonaws.com/xinput-calibrator_0.7.5-1_armhf.deb
sudo dpkg -i -B xinput-calibrator_0.7.5-1_armhf.deb

Before you start the xinput_calibrator you will need to delete the old calibration data so run

sudo rm /etc/X11/xorg.conf.d/99-calibration.conf

Before running startx and the calibrator - otherwise it gets really confused!

Now you'll have to run the xcalibrator while also running X. You can do this by startx and then opening up the terminal program and running the xinput_calibrator command OR you can do what we do which is run startx in a SSH/Terminal shell and then run the xinput_calibrator in the X window, which requires the following command order:

FRAMEBUFFER=/dev/fb1 startx &
DISPLAY=:0.0 xinput_calibrator

Follow the directions on screen

Crédit: AdaFruit Industries www.adafruit.com

Once complete you'll get something like:

Crédit: AdaFruit Industries www.adafruit.com

Run sudo nano /etc/X11/xorg.conf.d/99-calibration.conf and copy the

Section "InputClass"
    Identifier "calibration"
    MatchProduct "stmpe-ts"
    Option "Calibration" "119 3736 3850 174"
    Option "SwapAxes" "1"
EndSection

or whatever you got, into there. You can quit X if you want by typing fg to bring that command into the foreground, and then CONTROLE-C to quit.

Your touchscreen is now super calibrated, hurrah!

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Source: Adafruit PiTFT - 2.8" Touchscreen Display for Raspberry Pi
Créé par LadyAda pour AdaFruit Industries.
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Traduit avec l'autorisation d'AdaFruit Industries - Translated with the permission from Adafruit Industries - www.adafruit.com