WSAL21687 – 4inch DSI LCD/en

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 4inch DSI LCD (WSAL21687) is a capacitive touch display with an IPS panel, 480×800 resolution and optical bonding. It connects directly to a Raspberry Pi via the DSI interface and supports Pi5/CM5/4B/3B+/3A+/3B/CM3+/CM3 as well as Bookworm, Bullseye and Buster systems.

Related products at JW Tech

WSAL21687 – 4inch Capacitive Touch Display for Raspberry Pi, 480×800, DSI Interface, IPS, Optical Bonding Screen

Technical overview

Resolution: 480×800 pixels; IPS panel with optical bonding for improved image quality.
Five-point capacitive touch with toughened glass (hardness up to 6H).
Connects via DSI1 (recommended) or DSI0 depending on board; Pi5/CM4/CM3+/CM3 have two MIPI DSI interfaces.
Supported boards: Pi5, CM5, 4B, CM4, 3B+, 3A+, 3B, CM3+, CM3.
Supported operating systems: Bookworm, Bullseye and Buster.
For Bookworm/Bullseye: add dtoverlay=vc4-kms-dsi-waveshare-panel,4_0_inch to config.txt; DSI1 is the default.
For Buster: install the driver from the Waveshare-DSI-LCD repository (e.g. WS_xinchDSI_MAIN.sh 40 I2C0) or use a pre-installed image.
Display rotation via GUI settings (Screen Configuration → Screen → DSI-1/DSI-2); synchronized rotation of display and touch is fully supported only on Trixie according to the source.
Backlight brightness can be controlled by software.
Maximum refresh rate over DSI: 60 Hz.

Commands and examples – verify before use:

dtoverlay=vc4-kms-v3d
dtoverlay=vc4-kms-dsi-waveshare-panel,4_0_inch
git clone https://github.com/waveshare/Waveshare-DSI-LCD
cd Waveshare-DSI-LCD
sudo bash ./WS_xinchDSI_MAIN.sh 40 I2C0
sudo reboot
dtoverlay=WS_xinchDSI_Screen,SCREEN_type=1,I2C_bus=10
dtoverlay=WS_xinchDSI_Touch,invertedx,swappedxy,I2C_bus=10

Notes and version constraints

The exact kernel version must be checked before installing the driver (uname -a); the source references subdirectory 6.1.21 as an example – other kernel versions require choosing the matching directory.
System updates under Buster may overwrite previously installed driver files; the driver must then be reinstalled.
When changing the motherboard (e.g. from Pi4B to Pi3B+), the appropriate drivers must be reinstalled.
Synchronized rotation of display and touch is fully supported only on Trixie according to the source; on Bookworm/Buster the setting paths differ.
The DIP switch defaults to I2C-0; using the 40-pin I2C port (I2C-1) requires switching the DIP switch and using a 4-PIN header.
Beware of knock-offs: the source warns about untested copies without support – authenticity should be verified before purchase.

Source and revision record

4inch DSI LCD - Waveshare Wiki
Source revision: 105336
Captured: 2026-09-03T03:15:24+00:00
SHA-256: 1e79e96d8de4aa18d44768b0a3943e36c379f77a56976f9e998feb76c31c93fb