Zum Inhalt springen

WSAL16340 – 4inch HDMI LCD (H)/en

Aus JW Tech Wiki

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 4-inch resistive touch LCD with HDMI interface and IPS panel is designed primarily for Raspberry Pi devices. It provides a 480×800 resolution, an OSD menu for manual brightness/contrast adjustment, and a 3.5 mm jack for audio output via HDMI. The device can also be used as a computer monitor; in that case the touch panel is unavailable and an HDMI cable is required.

Related products at JW Tech

Technical overview

  • Resolution: 480 × 800 pixels on a 4-inch IPS panel.
  • Resistive touch input; the touch area requires GPIO connections to the Raspberry Pi.
  • Direct connection to various Raspberry Pi versions; for Pi Zero / Zero 2 W an additional HDMI cable is required.
  • Supported operating systems: Raspberry Pi OS, Ubuntu, Kali, and Retropie.
  • The OSD menu allows manual adjustment of brightness and contrast ratio.
  • Audio output via a 3.5 mm jack, supported by HDMI audio.
  • Hardware connection steps include: connecting the GPIO interface (Pi has 40 pins, display has 26 pins), connecting the HDMI connector, and setting the backlight switch on the back of the LCD to "ON".
  • For software setup, download the latest system image from the official Raspberry Pi website and write it to the TF card using SDFormatter and Win32DiskImager.
  • After writing the image, add the line dtoverlay=waveshare-ads7846,penirq=25,xmin=150,xmax=3900,ymin=100,ymax=3950,speed=50000 at the end of config.txt.
  • Touch calibration: adjust x_min, x_max, y_min, and y_max parameters; exact values can be determined using the evtest tool.
  • Display rotation methods depend on the OS: use the Screen Configuration app under Bookworm, use xrandr -o <angle> when KMS/FKMS driver is loaded, use display_rotate=<value> in config.txt without the driver, or use fbcon parameters in cmdline.txt under Ubuntu.
  • Operating temperature range is 0 °C to 70 °C.

Commands and examples – verify before use:  

dtoverlay=waveshare-ads7846,penirq=25,xmin=150,xmax=3900,ymin=100,ymax=3950,speed=50000
sudo apt-get install evtest
sudo evtest
sudo nano /boot/firmware/config.txt
dtoverlay=waveshare-ads7846,x_min=164,x_max=4010,y_min=154,y_max=3758
sudo reboot
sudo nano .config/wayfire.ini
[output:HDMI-A-1]
mode = 800x480@60
transform = 270
sudo nano /etc/xdg/lxsession/LXDE-pi/autostart
xrandr -o 1
display_rotate=3
fbcon=rotate:0 video=HDMI-A-1:800x480M@60,rotate=0
fbcon=rotate:3 video=HDMI-A-1:800x480M@60,rotate=90
fbcon=rotate:2 video=HDMI-A-1:800x480M@60,rotate=180
fbcon=rotate:1 video=HDMI-A-1:800x480M@60,rotate=270
dusable_splash=1
sudo -E rpi-eeprom-config --edit

Notes and version constraints

  • Exact touch calibration values (x_min, x_max, y_min, y_max) are device-specific and must be determined per unit using evtest.
  • Rotation parameters in config.txt (display_rotate) have different meanings depending on whether the KMS/FKMS driver is present; verify before applying whether dtoverlay=vc4-kms-v3d or dtoverlay=vc4-fkms-v3d is enabled.
  • When used as a standalone monitor (without Raspberry Pi), the touch panel is not usable; this must be accounted for in the target deployment.
  • Installation of xserver-xorg-input-evdev and xinput-calibrator may fail on Ubuntu/Kali; the source describes possible errors but does not provide a complete fix.
  • The commands reference specific file paths (e.g., /boot/config.txt vs. /boot/firmware/config.txt) which may vary across OS versions.
  • The operating temperature range (0–70 °C) applies only to the display itself; environmental effects on the Raspberry Pi are not covered here.

Source and revision record

Abgerufen von „https://wiki.jw-tech.eu/index.php?title=WSAL16340_–_4inch_HDMI_LCD_(H)/en&oldid=1732“