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Freigegebene technische Dokumentation veröffentlicht; Text-only und noindex

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'''Documentation notice:''' This technical documentation was independently rewritten from an archived supplier source. Check technical details and commands against the product version and manufacturer documentation before use.

== Summary ==
The Waveshare display is a 2.8-inch TFT with resistive touch, 320×240 resolution and direct GPIO connection to Raspberry Pi devices. The current Rev2.x hardware uses an updated driver approach; configuration is done via device-tree overlays in config.txt plus X11 settings for startx and touch calibration.

== Related products at JW Tech ==
* [https://shop.jw-tech.eu/p/WSAL12219 WSAL12219 – 2.8inch RPi LCD (A), 320×240]

== Technical overview ==
* Resolution: 320 × 240 pixels
* Display: 2.8-inch TFT with resistive touch
* Interface: direct connection to the Raspberry Pi 40-pin GPIO header
* Compatibility: works with all Raspberry Pi generations
* Driver: device-tree overlay waveshare28a-v2 copied to /boot/overlays
* config.txt receives SPI, HDMI and overlay entries for the display and the ADS7846 touch controller
* Auto-start: .bash_profile invokes startx on FRAMEBUFFER=/dev/fb1
* X11: 99-fbturbo.~ configures the fbdev driver on /dev/fb0
* Touch calibration: 99-calibration.conf defines calibration values and axis swap
* Normal operating current: about 80 mA
* Operating temperature range: commercial grade, 0–70 °C
* No pull-down resistors on the four buttons

'''Commands and examples – verify before use:'''
<syntaxhighlight lang="text">
sudo apt-get install unzip -y
sudo apt-get install cmake -y
wget https://files.waveshare.com/wiki/common/Waveshare28a-v2.zip
unzip ./Waveshare28a-v2.zip
sudo cp waveshare28a-v2.dtbo /boot/overlays/
sudo nano /boot/firmware/config.txt
dtparam=spi=on
dtoverlay=waveshare28a-v2
dtoverlay=ads7846,cs=1,penirq=17,penirq_pull=2,speed=50000,keep_vref_on=1,pmax=255,xohms=60
hdmi_force_hotplug=1
max_usb_current=1
hdmi_group=2
hdmi_mode=87
hdmi_cvt 480 320 60 6 0 0 0
hdmi_drive=2
display_rotate=0
sudo nano ~/.bash_profile
export FRAMEBUFFER=/dev/fb1
startx 2> /tmp/xorg_errors
sudo nano /usr/share/X11/xorg.conf.d/99-fbturbo.~
</syntaxhighlight>

== Notes and version constraints ==
* The exact lines in config.txt that should be blocked are only shown visually; manually verify which existing entries must be disabled.
* The download link to files.waveshare.com is an external resource; without network access in the sandbox environment it cannot be verified whether the file remains available.
* Calibration values (“198 3679 292 3800”) are device-specific and may vary by hardware batch; verify before reusing on other units.
* Automatic login assumes the username “pi”; if using another name, the procedure must be adapted.
* After full configuration, reboot takes longer and SSH needs a moment to become reachable – this is expected, not an error sign.
* If problems occur with older Raspberry Pi images: use the latest official or Waveshare image and install the newest driver.
* The hardware revision (Rev2.0 vs. older) can be identified by the silkscreen marking on the backside; a mismatch between firmware and driver can cause the display not to work.

== Source and revision record ==
* [https://www.waveshare.com/wiki/2.8inch_RPi_LCD_(A) 2.8inch RPi LCD (A) - Waveshare Wiki]
* Source revision: 107970
* Captured: 2026-08-30T03:18:02+00:00
* SHA-256: <code>e699f2fa8d43891ff020d85c058007cac27946857d80f17473b780c93d00928f</code>

WSAL12219 – 2.8inch RPi LCD (A)/en - Versionsgeschichte

JWTechPublisher: Freigegebene technische Dokumentation veröffentlicht; Text-only und noindex