DSI Screen

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. Compatible Screens

The Luckfox Lyra series supports the 10.1-DSI-TOUCH-A by default. Luckfox official, Raspberry Pi-compatible, and Waveshare DSI screens have also been adapted to provide display and touch functionality.

Use the built-in luckfox-config tool on the development board to select the configuration that matches the connected screen. For custom configurations, you can also modify the corresponding device tree by following the SDK device tree configuration guide. Reboot the development board after switching the screen configuration.

The resolution in each table is the native display mode used when selecting and testing the corresponding screen configuration.

Raspberry Pi DSI V1-Compatible Screens

Model	Resolution
4.3inch DSI LCD	800 x 480
5inch DSI LCD	800 x 480
7inch DSI LCD	800 x 480
8inch DSI LCD	800 x 480

Raspberry Pi-Compatible DSI Screens

Model	Resolution
2.8inch DSI	480 x 640
3.4inch DSI	800 x 800
4.0inch DSI	480 x 800
5.0inch / 7.0inch DSI	1024 x 600
7.9inch DSI	400 x 1280
8.0inch / 10.1inch DSI	1280 x 800
11.9inch DSI	320 x 1480
4.0inch DSI-C	720 x 720
5.0inch DSI-D	720 x 1280
6.25inch DSI	720 x 1560
8.8inch DSI	480 x 1920
7.0inch DSI-H	1280 x 720

Waveshare DSI Screens

Model	Resolution
10.1-DSI-TOUCH-A	800 x 1280
10.1-DSI-TOUCH-B / 9-DSI-TOUCH-B	720 x 1280
8.8-DSI-TOUCH-A	480 x 1920
8-DSI-TOUCH-A	800 x 1280
7-DSI-TOUCH-A	720 x 1280
7-DSI-TOUCH-C	1024 x 600
5.5-DSI-TOUCH-A	720 x 1280
5-DSI-TOUCH-A	720 x 1280
4.3-DSI-TOUCH-A	480 x 800
4-DSI-TOUCH-A	480 x 800
4-DSI-TOUCH-C	720 x 720
3.4-DSI-TOUCH-C	800 x 800

3. Hardware Connections

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

TIP

Please ensure the ribbon cable is connected correctly according to your specific development board model. If the screen fails to light up immediately after switching, power off the device immediately and check the wiring to avoid potential damage or other abnormal behavior.

Use a 22PIN FPC cable to connect the display’s DSI interface to the DSI interface on the Luckfox-Lyra motherboard.
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/Lyra Plus：
- **Luckfox Lyra Ultra/Ultra W **：
- Luckfox Lyra Zero W：
- Luckfox Lyra Pi：

3.2 Luckfox Lyra Connecting to Raspberry Pi DSI Screen

Use a 15PIN to 22PIN FPC cable Pi5-Display-Cable.
- Luckfox Lyra/Lyra Plus：
- Luckfox Lyra/Lyra Plus：
- Luckfox Lyra Zero W：
- Luckfox Lyra Pi：

4. Software Configuration

For individual developers, we provide a more convenient screen switching solution — use the built-in tool luckfox-config on the development board to select the target screen model without manually modifying the device tree. For more details, see:luckfox-config《3.6 DSI配置》
Users may also manually modify the corresponding device tree configuration if needed.as detailed in theSDK Environment Deployment "6. Device tree configuration"

5. 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]

6. Display Test

Use modetest on the Lyra to display a color-bar test pattern. The Connector ID, CRTC ID, and resolution must match the currently selected screen configuration.

Query the DSI connector and its available display mode:
```
modetest -M rockchip | grep -A10 "Connectors:"
```
Find the DSI-1 row whose status is connected. The first column is the Connector ID. Under modes, the #0 row shows the resolution exposed by the current screen configuration.
Query the CRTC ID:
```
modetest -M rockchip | grep -A10 "CRTCs:"
```
The first column of the active CRTC row is the CRTC ID. Its size should match the resolution reported for DSI-1.

Run the standard color-bar test using the detected IDs and resolution:

modetest -M rockchip -s <Connector ID>@<CRTC ID>:<width>x<height>

For example, if the Connector ID is 74 and the CRTC ID is 71, use the command that matches the connected screen:

Screen	Test command
10.1-DSI-TOUCH-A (`800 x 1280`)	`modetest -M rockchip -s 74@71:800x1280`
7-DSI-TOUCH-C (`1024 x 600`)	`modetest -M rockchip -s 74@71:1024x600`
4-DSI-TOUCH-C (`720 x 720`)	`modetest -M rockchip -s 74@71:720x720`

To display the diagonal color-bar pattern, append -Ftiles:

modetest -M rockchip -s <Connector ID>@<CRTC ID>:<width>x<height> -Ftiles

tip

The IDs in the examples are for reference only and may differ between software versions. Always use the IDs and resolution reported by modetest. If the expected resolution does not appear under DSI-1, select the matching screen configuration with luckfox-config or update the device tree, then reboot before testing again.

7. 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]:
```

8. 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

1. Introduction​

2. Compatible Screens​

Raspberry Pi DSI V1-Compatible Screens​

Raspberry Pi-Compatible DSI Screens​

Waveshare DSI Screens​

3. Hardware Connections​

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

3.2 Luckfox Lyra Connecting to Raspberry Pi DSI Screen​

4. Software Configuration​

5. Viewing Screen Information​

6. Display Test​

7. Touch Test​

8. Backlight Control​