Latest revision as of 11:36, 30 November 2023

4inch DPI LCD (C)

4inch Square Capacitive Touch Screen LCD (C) for Raspberry Pi, 720 × 720, DPI, IPS

Introduction

4inch Square Capacitive Touch Screen LCD (C) for Raspberry Pi, 720 × 720, DPI, IPS, toughened glass cover, low power solution.

Features

4inch IPS Display, 720 x 720 hardware resolution.
Designed for Raspberry Pi, based on Raspberry Pi 40pin GPIO interface.
Using DPI666 interface of Raspberry Pi to drive LCD, refresh rate up to 60Hz.
Drive capacitive touch through I2C interface of Raspberry Pi, 5-point touch, toughened glass panel, hardness up to 6H.
Supports Raspberry Pi OS / Ubuntu / Kali systems.

Using with Raspberry Pi

Hardware connection

Please install the display slowly on the 40PIN GPIO interface of the Raspberry Pi as shown below.

Software setting

If you don't know the difference between the two branches of Raspberry Pi OS, you can check the following introduction #Introducing the Raspberry Pi OS fork

For Raspberry Pi OS Bullseye branch

Please download the latest version of the image from the Raspberry Pi official website.
1. Download the compressed file to the PC, and extract the img file.
2. Connect the TF card to the PC and use SDFormatter to format the TF card.
3. Open the Win32DiskImager software, select the system image prepared in step 1, and click write to burn the system image.
4. After the programming is completed, open the config.txt file in the root directory of the TF card, add the following code at the end of config.txt, and save it.

dtoverlay=vc4-kms-v3d
dtoverlay=vc4-kms-DPI-4inch
dtoverlay=waveshare-4dpic-3b-4b
dtoverlay=waveshare-4dpic-3b
dtoverlay=waveshare-4dpic-4b

5. Download the 4inch DPI LCD (C)-KMS display file and put it in the /boot/overlays directory of the TF card, and eject the TF card safely.
6. Insert the TF card into the Raspberry Pi, power on the Raspberry Pi, and wait for about thirty seconds to display normally.

For Raspberry Pi OS Buster branch and Ubuntu system

1. Open the config.txt file in the root directory of the TF card, add the following code at the end of config.txt, save and safely eject the TF card.

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
dtoverlay=waveshare-4dpic-3b-4b
dtoverlay=waveshare-4dpic-3b
dtoverlay=waveshare-4dpic-4b

2. Download the 4inch DPI LCD (C)-KMS display file and put it in the /boot/overlays directory of the TF card, and eject the TF card safely.
3. Insert the TF card into the Raspberry Pi, power on the Raspberry Pi, and wait for about thirty seconds to display normally.

Introducing the Raspberry Pi OS fork

On December 2, 2021, the Raspberry Pi OS for Raspberry Pi split into two branches, the Buster branch, and the Bullseye branch.

The Buster branch is a continuation of the old system, which is more stable and uses raspicam as the default camera subsystem.

The Bullseye branch adds some new features, including KMS as the default display driver and libcamera as the default camera subsystem.
Image download address

More detailed information can be found at:

Raspberry Pi Branch Details

Buster Release Notes

Bullseye Release Notes

Notes: The above information was updated on January 24, 2022. Due to the frequent update of the Raspberry Pi image, when you see this information, the relevant information may be out of date. The actual performance of the image shall prevail. This is for reference only.

Screen orientation settings

Update software version

Raspberry Pi OS Bullseye branch needs to update the software version, and this step can be omitted for other systems.

sudo apt-get update
sudo apt-get full-upgrade

Raspberry Pi OS and Kali display rotation

First, check whether the KMS or FKMS driver is loaded on the system you are using.

Check method: In /boot/config.txt, check whether the line dtoverlay=vc4-kms-v3d or dtoverlay=vc4-fkms-v3d is turned on.

With KMS or FKMS driver loaded

Use the following command for display rotation:

sudo nano /etc/xdg/lxsession/LXDE-pi/autostart
#Enter the command corresponding to the display rotation angle at the end of the autostart file, and it will take effect after rebooting the system.
#0: rotate 0 degrees; 1: rotate 270 degrees; 2: rotate 180 degrees; 3: rotate 90 degrees
xrandr -o 1

No KMS or FKMS driver loaded

Use the following command for display rotation:

sudo nano /boot/config.txt
#Enter the command corresponding to the display rotation angle at the end of the config.txt file, and it will take effect after rebooting the system.
#0: rotate 0 degrees; 1: rotate 90 degrees; 2: rotate 180 degrees; 3: rotate 270 degrees
display_rotate=3

Touch Rotating

After the display is rotated, the position of the touch is incorrect because the touch doesn't change with the display angle. So the touch also needs to be modified.

1. Install libinput.

sudo apt-get install xserver-xorg-input-libinput

If the system you installed is Ubuntu or Jetson Nano. The installation code is:

sudo apt install xserver-xorg-input-synaptics

2. Create the xorg.conf.d directory under /etc/X11/ (if the directory already exists, proceed directly to step 3).

sudo mkdir /etc/X11/xorg.conf.d

3. Copy the 40-libinput-conf file to the directory you created just now.

sudo cp /usr/share/X11/xorg.conf.d/40-libinput.conf /etc/X11/xorg.conf.d/

4. Edit this file.

sudo nano /etc/X11/xorg.conf.d/40-libinput.conf

Find the part of the touchscreen, add the following statement inside, and then save the file.

Option "CalibrationMatrix" "0 1 0 -1 0 1 0 0 1"

Similar to the picture below:

5. save and reboot your Pi.

sudo reboot

After completing these steps. The LCD could rotate 90 degrees for both the display and touch function.

Note:

90 degrees: Option "CalibrationMatrix" "0 1 0 -1 0 1 0 0 1"

180 degrees: Option "CalibrationMatrix" "-1 0 1 0 -1 1 0 0 1"

270 degrees: Option "CalibrationMatrix" "0 -1 1 1 0 0 0 0 1"

Others

Disable power saving

If you want to keep the display turning on all the time, you can disable the power-saving function.
Modify file lightdm.conf

sudo nano /etc/lightdm/lightdm.conf

Find the [SeatDefaults] option and uncomment the line"xserver-command", modify it as below:

#xserver-command=X

Modify this code to

xserver-command=X -s 0 -dpms

-s # –Disable the display protection.
dpms Disable power saving.

Reboot

sudo reboot

Turn on/off HDMI output

You can use the following commands to disable/enable the displaying.

vcgencmd display_power 0
vcgencmd display_power 1

Adjust brightness by PWM

Update wiringPi if you use Pi4.

wget https://project-downloads.drogon.net/wiringpi-latest.deb
sudo dpkg -i wiringpi-latest.deb
gpio -v
# It should be 2.52 version

Change the brightness with the following command:

gpio -g mode 18 pwm      #Set the pin for PWM
gpio pwmc 100   
gpio -g pwm 18 0         #Bightest
gpio -g pwm 18 1023      #Dimest
gpio -g mode 18 out      #Clean the GPIO

Raspberry Pi Long Right-click Software Installation

Test environment: 2022-04-04-raspios-bullseye-armhf 32-bit system.
Supported Models: Supports Waveshare Electronics DSI LCD, DPI LCD, and HDMI LCD capacitive touch screen series.

wget https://files.waveshare.com/upload/1/18/Evdev-right-click-emulation.zip
unzip Evdev-right-click-emulation.zip
cd evdev-right-click-emulation
sudo apt install build-essential libevdev2 libevdev-dev
cd 'evdev-right-click-emulation'
sudo cp 'out/evdev-rce' '/usr/local/bin/'
sudo chmod +x '/usr/local/bin/evdev-rce'

Enter the command:

sudo evdev-rce

After running, you can touch and long press to realize the right-click function.

Set IP

sudo usermod -G 'input' -a pi
echo 'uinput' | sudo tee -a /etc/modules
sudo nano  /etc/udev/rules.d/99-uinput.rules

Add in 99-uinput.rules file.

KERNEL=="uinput", MODE="0660", GROUP="input"

save it and run it in the terminal.

sudo udevadm control --reload-rules
sudo udevadm trigger

Then reboot:

sudo reboot

Run after reboot (no sudo needed at this point)

evdev-rce

After running, you can touch and long press to realize the right-click function.

Set Startup

Enter the terminal:

sudo mkdir ~/.config/autostart
sudo nano ~/.config/autostart/right_click.desktop

Add the following in right_click.desktop.

[Desktop Entry]
Version=1.0
Type=Application
Name=evdev-rce
GenericName=Enable long-press-to-right-click gesture
Exec=env LONG_CLICK_INTERVAL=1000 LONG_CLICK_FUZZ=200  /usr/local/bin/evdev-rce
Terminal=true
StartupNotify=false
#If you want to modify the sensitivity, you can modify the size of the two parameters, LONG_CLICK_INTERVAL=1000 LONG_CLICK_FUZZ=200.

Interface

The pins labeled "NC" below mean that those pins of Raspberry Pi are not occupied by the LCD, and the user can use them for other applications.

PIN NO.	SYMBOL	DESCRIPTION
1	NC	Power positive (3.3V power input)
2	5V	Power positive (5V power input)
3	VSYNC	Vertical sync
4	5V	Power positive (5V power input)
5	HSYNC	Horizontal sync
6	GND	Ground
7	B0	RGB signal cable
8	G2	RGB signal cable
9	GND	Ground
10	G3	RGB signal cable
11	G5	RGB signal cable
12	AUDIO	Audio output
13	TP_INT	Touch Panel interrupt
14	GND	Ground
15	R2	RGB signal cable
16	R3	RGB signal cable
17	NC	Power positive (3.3V power input)
18	R4	RGB signal cable
19	TP_SDA	I2C SDA for touch panel
20	GND	Ground
21	B5	RGB signal cable
22	R5	RGB signal cable
23	TP_SCL	I2C SCL for touch panel
24	B4	RGB signal cable
25	GND	Ground
26	B3	RGB signal cable
27	LCD_CLK	LCD clock
28	DE	LCD data enable
29	B1	RGB signal cable
30	GND	Ground
31	B2	RGB signal cable
32	G0	RGB signal cable
33	G1	RGB signal cable
34	GND	Ground
35	NC	GPIO interface
36	G4	RGB signal cable
37	NC	GPIO interface
38	R0	RGB signal cable
39	GND	Ground
40	R1	RGB signal cable

Resource

3D Drawing

4inch DPI LCD(C) 3D Drawing

Software

Anti-Piracy

Since the first-generation Raspberry Pi released, Waveshare has been working on designing, developing, and producing various fantastic touch LCDs for the Pi. Unfortunately, there are quite a few pirated/knock-off products in the market. They're usually some poor copies of our early hardware revisions, and comes with none support service.

To avoid becoming a victim of pirated products, please pay attention to the following features when purchasing:

(Click to enlarge)

Beware of knock-offs

Please note that we've found some poor copies of this item in the market. They are usually made of inferior materials and shipped without any testing.

You might be wondering if the one you're watching or you've purchased in other non-official stores is original, feel free to contact us.

Support

Technical Support

If you need technical support or have any feedback/review, please click the Submit Now button to submit a ticket, Our support team will check and reply to you within 1 to 2 working days. Please be patient as we make every effort to help you to resolve the issue.
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