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WSAL19742 – 4inch DPI LCD (C)/en

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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 4inch display is a square capacitive touchscreen with 720×720 resolution, an IPS panel and toughened glass. It connects via the Raspberry Pi's 40-pin GPIO header and is driven through the DPI666 interface; refresh rate reaches up to 60 Hz.

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Technical overview

  • Resolution: 720 × 720 pixels (square).
  • Panel type: IPS with capacitive 5-point touch over I²C.
  • Toughened glass with hardness up to 6H.
  • Connects via the Raspberry Pi's 40-pin GPIO header.
  • Driven through the DPI666 output, refresh rate up to 60 Hz.
  • Supported operating systems: Raspberry Pi OS (Bookworm/Bullseye/Buster) and Ubuntu.
  • Power consumption: 5 V at 160 mA.
  • For Bookworm and Bullseye, specific dtoverlay entries must be added to config.txt; additionally a KMS overlay file must be placed under /boot/overlays.
  • Display rotation is done either via the “Screen Configuration” GUI or via cmdline.txt / config.txt depending on OS version.
  • Touch rotation requires separate calibration files (udev rules or Xorg configuration), because display and touch rotation are not automatically synchronized (except on Bookworm).

Commands and examples – verify before use:  

dtoverlay=vc4-kms-v3d
dtoverlay=vc4-kms-DPI-4inch
dtoverlay=waveshare-4dpic-3b-4b
dtoverlay=waveshare-4dpic-3b
dtoverlay=waveshare-4dpic-4b
dtoverlay=waveshare-4dpi
dtoverlay=waveshare-touch-4dpi
gpio=0-9=a2
gpio=12-17=a2
gpio=20-25=a2
dtoverlay=dpi24
enable_dpi_lcd=1
display_default_lcd=1
extra_transpose_buffer=2
dpi_group=2
dpi_mode=87
dpi_output_format=0x7f216
dpi_timings=720 0 46 2 42 720 0 16 2 18 0 0 0 60 0 60000000 6
video=DPI-1:720x720M@60,rotate=90
video=DPI-1:720x720M@60,rotate=180

Notes and version constraints

  • The exact overlay file (“4inch DPI LCD (C)-KMS display file”) must be downloaded separately and placed under /boot/overlays; without it the display may not work.
  • When using both DPI and HDMI outputs simultaneously, they share the same rotation value via cmdline.txt – independent per-output rotation is not possible.
  • Long cables (> 10 cm) on the DPI connector are not recommended, as the parallel high-speed lines can cause signal interference, image jitter, or display failures.
  • Touch rotation must be configured manually on Bullseye/Buster; only Bookworm supports synchronized rotation via the GUI.
  • The power figure (5 V / 160 mA) comes from the source; actual consumption may vary with configuration.
  • Knock-offs and counterfeit units are circulating; verify authenticity before purchase.

Source and revision record

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