RASP-PiTFT-PLUS-Touch
Introduction
If you've grabbed our Easy Install image, or use the script, this step is not required, it's already done! This is just for advanced users who are curious on how to configure and customize the touchscreen |
Crédit: AdaFruit Industries www.adafruit.com
Configurer l'écran 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
Script de calibration automatique
If you rotate the display you need to recalibrate the touchscreen to work with the new screen orientation. You can manually run the calibration processes in the next section, or you can run a small Python script which will automatically set a default touchscreen calibration based on the screen orientation.
This helper is automatically installed for you but if you'd like you can check it out here on github
Run it at the command line with sudo adafruit-pitft-touch-cal
it will try to figure out what display you have installed and the rotation it's set up for
Crédit: AdaFruit Industries www.adafruit.com
By default the script will attempt to read the screen orientation by examining the PiTFT module configuration with modprobe. If the script can read the orientation it will print out the current orientation, the current touchscreen calibration values, and the new touchscreen calibration values baesd on the current orientation. Before updating the calibration the script will ask you to confirm that you'd like to make the change. Press y and enter to confirm.
Crédit: AdaFruit Industries www.adafruit.com
Try using this default calibration script to easily calibrate your touchscreen display. Note that the calibration values might not be exactly right for your display, but they should be close enough for most needs. If you need the most accurate touchscreen calibration, follow the steps in the next section to manually calibrate the touchscreen.
Calibration Manuelle
If you rotate the display you have some other setup where you need to carefully calibrate you can do it 'manually'
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
You should see five crosshair targets. If you see less than that, the touchscreen probably generated multiple signals for a single touch, and you should try calibrating again. |
Crédit: AdaFruit Industries www.adafruit.com
Next you can run {{{1}}} 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 (which is challenging to do on such a small screen) OR you can do what we do which is run startx in a SSH/Terminal shell and then run the xinput_calibrator from the same shell, 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
Source: Adafruit PiTFT 3.5" Touch Screen for Raspberry Pi
Créé par LadyAda pour AdaFruit Industries.
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