4inch RPi LCD (C)
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Overview
Introduction
4 inch Touch Screen TFT LCD Designed for Raspberry Pi, High-Speed SPI transmission.
Features
- The hardware resolution is 480 × 320.
- Resistive touch control.
- It is compatible and can be directly inserted into any version of Raspberry Pi.
- Support 125MHz high-speed SPI signal transmission, which makes the screen display clear and stable.
- Provides drivers (works with your own Raspbian/Ubuntu/Kali and Retropie system directly).
- Support FBCP software driver, which can set the software resolution and dual-screen display.
- Immersion gold design, fine carving.
Getting Started
Hardware Connection
- There are 40 pins on Raspberry Pi, but there are 26 pins on the LCD, so you should pay attention to connecting the pins to your Pi accordingly.
Install the touch driver
The RPi LCD can be driven in two ways:
Method 1. Install a driver to your Raspbian OS.
Method 2. Use the Ready-to-use image file of which the LCD driver was pre-installed.
Method 1. Driver installation
Please download the latest version of the image on the Raspberry Pi official website. (Raspbian/Ubuntu Mate/Kali or Retropie)
1) Download the compressed image file to the PC, and unzip it to get the .img file.
2) Connect the TF card to the PC, open the Win32DiskImager software, select the system image downloaded in step 1, and click 'Write' to write the system image. (How to write an image to a micro SD card for your Pi? See RPi Image Installation Guides for more details.)
3) Connect the TF card to the Raspberry Pi, and start the Raspberry Pi. The LCD will display after booting up, and then log in to the Raspberry Pi terminal,(You may need to connect a keyboard and HDMI LCD to Pi for driver installation, or log in remotely with SSH.)
4) Then open the terminal of Raspberry Pi to install the touch driver.
git clone https://github.com/waveshare/LCD-show.git cd LCD-show/
Note: The Raspberry Pi must be connected to the network, or else the touch driver won't be successfully installed.
chmod +x LCD4C-show ./LCD4C-show
The touch function will work after restart. For ease of use, you can set the screen orientation, see: #Screen orientation settings.
Notes:
- 1. Executing apt-get upgrade will cause the LCD to fail to work properly. In this case, you need to edit the config.txt file in the SD card and delete this sentence: dtoverlay=ads7846.
- 2. When working with Raspbian-lite, the command of the touch driver installation should be:
./LCD4C-show lite
Method 2. Using Ready-to-use image
The image file with the pre-installed driver is located in the IMAGE directory of the CD, or you can download it from #Image. Extract the .7z file and you will get an .img file. Write the image to your micro SD card (How to write an image to a micro SD card for your Pi? See RPi Image Installation Guides for more details). Then insert the card into your Pi, power up, and enjoy it.
Screen orientation settings
After installing the touch driver, you can modify the screen rotation direction by running the following commands.
cd LCD-show/ #X can be 0, 90, 180 and 270. Indicates that the LCD rotates 0 degrees, 90 degrees, 180 degrees and 270 degrees, respectively. #If it is an old version, execute the following code: sudo ./LCD28-show X #If it is a new version, execute the following code: sudo ./LCD28-show-V2 X
The rotation command under Raspbian-lite is as follows:
cd LCD-show/ #X can be 0, 90, 180 and 270. Indicates that the LCD rotates 0 degrees, 90 degrees, 180 degrees and 270 degrees, respectively. #If it is an old version, execute the following code: sudo ./LCD28-show lite X #If it is a new version, execute the following code: sudo ./LCD28-show-V2 lite X
Touch screen calibration
This LCD can be calibrated through the xinput-calibrator program. Note: The Raspberry Pi must be connected to the network, or else the program won't be successfully installed.
- Run the following command to install:
sudo apt-get install xinput-calibrator
- Click the "Menu" button on the taskbar, choose "Preference" -> "Calibrate Touchscreen".
- Finish the touch calibration following the prompts. Maybe rebooting is required to make calibration active.
- You can create a 99-calibration.conf file to save the touch parameters (not necessary if file exists).
sudo nano /etc/X11/xorg.conf.d/99-calibration.conf
- Save the touch parameters (may differ depending on LCD) to 99-calibration.conf, as shown in the picture:
Control Backlight Brightness with GPIO
Use a 0R resistor or solder to connect this pad.
Execute the following command on the Raspberry Pi terminal to control the backlight brightness:
gpio -g pwm 18 1024 gpio -g mode 18 pwm (the occupied pins are PWM pins) gpio pwmc 1000 gpio -g pwm 18 X (control brightness, X value is between 0~1024)
Install Virtual Keyboard
1. Install matchbox-keyboard.
sudo apt-get install update sudo apt-get install matchbox-keyboard sudo nano /usr/bin/toggle-matchbox-keyboard.sh
2. Copy the statements below to toggle-matchbox-keyboard.sh and save.
#!/bin/bash #This script toggle the virtual keyboard PID=`pidof matchbox-keyboard` if [ ! -e $PID ]; then killall matchbox-keyboard else matchbox-keyboard -s 50 extended& fi
3. Execute the commands:
sudo chmod +x /usr/bin/toggle-matchbox-keyboard.sh sudo mkdir /usr/local/share/applications sudo nano /usr/local/share/applications/toggle-matchbox-keyboard.desktop
4. Copy the statements to toggle-matchbox-keyboard.desktop and save.
[Desktop Entry] Name=Toggle Matchbox Keyboard Comment=Toggle Matchbox Keyboard` Exec=toggle-matchbox-keyboard.sh Type=Application Icon=matchbox-keyboard.png Categories=Panel;Utility;MB X-MB-INPUT-MECHANSIM=True
5. Execute commands as below. Note that you need to use "Pi " user permission instead of root to execute this command.
sudo nano /etc/xdg/lxpanel/LXDE-pi/panels/panel
6. Find the statement which is similar to the one below: (It may be different in different versions)
Plugin {
type = launchbar
Config {
Button {
id=lxde-screenlock.desktop
}
Button {
id=lxde-logout.desktop
}
}
7. Append these statements to add a button option:
Button {
id=/usr/local/share/applications/toggle-matchbox-keyboard.desktop
}
8. Reboot your Raspberry Pi. If the virtual keyboard is installed correctly, you can find that there is a keyboard icon on the left of the bar:
sudo reboot
Configure Camera
- Edit config.txt file
sudo nano /boot/firmware/config.txt
Add the following code at the end of the config.txt
dtoverlay=vc4-kms-v3d max_framebuffers=2
- Edit the 98-spi-screen.conf configuration file
sudo nano /etc/X11/xorg.conf.d/98-spi-screen.conf
Add the following to the 98-spi-screen.conf configuration file
Section "Device" Identifier "SPI Screen" Driver "fbdev" Option "fbdev" "/dev/fb0" EndSection
Reboot to take effect
sudo reboot
- Turn on the camera:
libcamera-hello --qt-preview
Interface
The pins labeled "NC" below means 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, 17 | 3.3V | Power positive (3.3V power input) |
| 2, 4 | 5V | Power positive (5V power input) |
| 3, 5, 7, 8, 10, 12, 13, 15, 16 | NC | NC |
| 6, 9, 14, 20, 25 | GND | Ground |
| 11 | TP_IRQ | Touch Panel interrupt, low level while the Touch Panel detects touching |
| 18 | LCD_RS | Command/data register selection |
| 19 | LCD_SI / TP_SI | LCD display/SPI data input of Touch Panel |
| 21 | TP_SO | SPI data output of Touch Panel |
| 22 | RST | Reset |
| 23 | LCD_SCK / TP_SCK | LCD display/SPI clock of Touch Panel |
| 24 | LCD_CS | LCD chip selection, low active |
| 26 | TP_CS | Touch Panel chip selection, low active |
Resources
Documents
Image
Description: if you felt hard to install the driver, try the image with the driver pre-installed.
Displaying Area
Driver
The driver can be downloaded from github
git clone https://github.com/waveshare/LCD-show.git
Software
FAQ
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Since the Raspberry Pi image and version are frequently updated, if you encounter a situation where the LCD cannot be used normally, please download the latest version of the image provided by us or from the official website of Raspberry Pi and install the latest driver provided by us.
- Make sure the hardware connection is correct and the contact is good.
- Make sure that TF card programming is normal.
- When the Raspberry Pi starts normally, the PWR light is always on, and the ACT light is flashing. If it is found that both lights are always on, it may be that the TF card is not successfully programmed to the image or the TF card is in poor contact with the Raspberry Pi.
- It is recommended to use a 5V 2.5A power adapter for the Raspberry Pi. If the Raspberry Pi is powered by the USB port of the PC, the Raspberry Pi may not be able to start normally due to an insufficient power supply.
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200mA.
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Support
Technical Support
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