Skip to main content

DSI

1. Introduction​

DSI (Display Serial Interface) is a high-speed serial communication interface used between display panels and display controllers, widely used in mobile devices, embedded systems, tablets, and other systems requiring high-performance displays. It is standardized by the MIPI (Mobile Industry Processor Interface) Alliance, designed to reduce the number of pins on devices and optimize power consumption.

2. Hardware Connections​

Luckfox Lyra Connecting to 10.1-DSI-TOUCH-A Screen​

  1. Use a 22PIN FPC cable to connect the display’s DSI interface to the DSI interface on the Luckfox-Lyra motherboard. (Note: The blue end of the cable should face the development board’s chip.)
  2. Use an MX1.25 2PIN to 4PIN connector cable to connect the display’s power interface to the USB MX1.25 4P interface on the Luckfox-Lyra motherboard. As shown below:

Luckfox Lyra Connecting to Raspberry Pi DSI Screen​

  1. Use a 15PIN to 22PIN FPC cable Pi5-Display-Cable. (Note: The black end of the cable should face the development board’s chip.)

3. Compatible Screens​

The Luckfox Lyra series development board supports the 10.1-DSI-TOUCH-A by default. In addition, we have adapted official Luckfox, Raspberry Pi, and Waveshare DSI screens to ensure their display and touch functionalities work properly. To use the following screens, users need to modify the related device tree configuration, as detailed in theSDK Environment Deployment "6. Device tree configuration"

3.1 Official Luckfox DSI Screens and Compatible Screens (Resolution: 800 x 480)​

ModelWiki Address
4.3″ DSI Touchscreenhttps://www.luckfox.com/Displays/EN-4.3inch-DSI-Touchscreen
5″ DSI Touchscreenhttps://www.luckfox.com/Displays/EN-5inch-DSI-Touchscreen
7″ DSI Touchscreenhttps://www.luckfox.com/Displays/EN-7inch-DSI-Touchscreen
8inch DSI LCDhttps://www.waveshare.com/8inch-dsi-lcd.htm

3.2 Waveshare DSI Screens​

ModelWiki Address
10.1inch DSI LCD (C)https://www.waveshare.com/wiki/10.1inch_DSI_LCD_(C)
8inch DSI LCD (C)https://www.waveshare.com/wiki/8inch_DSI_LCD_(C)
7inch DSI LCD (C)https://www.waveshare.com/wiki/7inch_DSI_LCD_(C)
5inch DSI LCD (C)https://www.waveshare.com/wiki/5inch_DSI_LCD_(C)
2.8inch DSI LCDhttps://www.waveshare.com/wiki/2.8inch_DSI_LCD
4inch DSI LCDhttps://www.waveshare.com/wiki/4inch_DSI_LCD
7.9inch DSI LCDhttps://www.waveshare.com/wiki/7.9inch_DSI_LCD
8.8inch DSI LCDhttps://www.waveshare.com/wiki/8.8inch_DSI_LCD
11.9inch DSI LCDhttps://www.waveshare.com/wiki/11.9inch_DSI_LCD
3.4inch DSI LCD (C)https://www.waveshare.com/wiki/3.4inch_DSI_LCD_(C)
4inch DSI LCD (C)https://www.waveshare.com/wiki/4inch_DSI_LCD_(C)
5inch DSI LCD (D)https://www.waveshare.com/wiki/5inch_DSI_LCD_(D)
6.25inch DSI LCDhttps://www.waveshare.com/wiki/6.25inch_DSI_LCD
101M-8001280-IPS-CT-Khttps://www.waveshare.com/wiki/101M-8001280-IPS-CT-K

4. Viewing Screen Information​

  • The screen ID available on the current system can be viewed with the following command:

    cat /sys/kernel/debug/dri/0/summary

  • Output:

    VOP [ff600000.vop]: ACTIVE
        Connector: DSI-1
            bus_format[100a]: RGB888_1X24
            overlay_mode[0] output_mode[0]color-encoding[1] color-range[1]
        Display mode: 800x1280p60
            dclk[70000 kHz] real_dclk[69475 kHz] aclk[294912 kHz] type[48] flag[a]
            H: 800 840 860 880
            V: 1280 1310 1314 1324
        win1-0: ACTIVE
            format: XR24 little-endian (0x34325258) SDR[0] color-encoding[0] color-range[0]
            csc: y2r[0] r2r[0] r2y[0] csc mode[0]
            zpos: 0
            src: pos[0x0] rect[800x1280]
            dst: pos[0x0] rect[800x1280]
            buf[0]: addr: 0x06100000 pitch: 3200 offset: 0
        post: sdr2hdr[0] hdr2sdr[0]
        pre : sdr2hdr[0]
        post CSC: r2y[0] y2r[0] CSC mode[2]

5. Display Test​

Use modetest on Lyra to perform a color bar test to validate display output:

  • Vertical Bar Test (Standard mode):

    modetest -M rockchip -s 74@71:800x1280

  • Diagonal Bar Test (Enable tile format):

    modetest -M rockchip -s 74@71:800x1280 -Ftiles

6. Touch Test​

  • Use the evtest command to test the touchscreen and check the response of the touch input device. Execute the following command:

    evtest

  • After running the command, the terminal will show output similar to the following. Press “0” to start the touchscreen test, and the terminal will print the event values triggered by the touch actions:

    No device specified, trying to scan all of /dev/input/event*
    Available devices:
    /dev/input/event0:      2-005d Goodix Capacitive TouchScreen
    Select the device event number [0-0]:

7. Backlight Control​

Other compatible screens share the same driver, supporting 0~255 levels of backlight control. The command for backlight control is:

# brightness level:0 ~ 255
echo <brightness level> > /sys/class/backlight/waveshare_bl/brightness