Rockchip (EASY EAI) RV1126B MIPI-DSI Output

HDMI OUT

1. Introduction to MIPI-DSI

MIPI (Mobile Industry Processor Interface): An interface standard defined by a consortium founded in 2003 by companies including ARM, Nokia, ST, and TI. Its purpose is to standardize internal interfaces of mobile devices such as mobile phones (e.g., camera interfaces, display interfaces, RF/baseband interfaces), thereby reducing the design complexity of mobile devices and increasing design flexibility.

Work Groups: The MIPI Alliance includes numerous work groups, each responsible for defining standards for corresponding devices. These include over a dozen work groups such as the Camera Working Group, Display Working Group, and High-Speed Multi-Link Working Group.

The MIPI DSI interface is the DSI (Display Serial Interface) standard specified by the Display Working Group under the MIPI Alliance.

1.1 EASY EAI Nano-TB DSI

• The DSI interface does not support hot-swapping and has specific power supply requirements. To use the DSI interface, ensure the power supply is a DC12V-3A input; otherwise, insufficient power will prevent the DSI screen from operating properly (a typical symptom is repeated reboots during the uboot phase).

1.2 Cable Specifications

• Reverse cable: Blue markings on both ends are on opposite sides.
• Straight cable: Blue markings on both ends are on the same side.

1.3 Hardware Interface Instructions

• The MIPI interface does not support hot-swapping—all wiring must be performed with power disconnected.
• Use a straight cable to connect the screen to the MIPI-DSI0 interface. (Caution: Using the wrong cable may damage the camera or core board—exercise extreme care during wiring.)
• The cable connector latch and the blue plastic marking on the FPC cable must be on the same side (as shown in the figure below).

2. Driver Support Instructions

The default firmware configures MIPI-DSI to support an 8-inch MIPI display. To enable system support for displays of other sizes or models, the kernel image must be modified and replaced. Follow these steps:

2.1 Upgrade to the Latest Firmware

For firmware download and specific flashing procedures, refer to the document《Firmware Flashing and Update》if unfamiliar.

2.2 Download Ubuntu System SDK Source Code

Download the ubuntu_sdk source code (primarily kernel source code) by following the instructions in《Embedded Low-Level Development / Ubuntu System SDK / Source Code Acquisition.》

2.3 Modify the Kernel Device Tree

Follow the guidelines in 《Embedded Low-Level Development / Ubuntu System SDK / Kernel 》to build and manage the kernel source code development repository as needed.

Modify the device tree file in the kernel source code repository as illustrated in the figure below:

EASY-EAI-Nano-TB device tree entry: arch/arm64/boot/dts/rockchip/rv1126b-nano.dts

Compile the kernel to generate a new boot.img.

2.4 Update the Kernel Image

• Copy the newly generated boot.img to the rockdev directory of the firmware package, replacing the original boot.img.
• Flash the updated boot.img to the development board.

3. Display Effects

3.1 Default Display Effect

After confirming correct wiring, power on the device—the boot logo shown in the figure below will be displayed.

3.2 Replace the Boot Logo

To replace the boot logo, follow the instructions in the document《Application Notes / Method for Replacing Boot Logo.》

3.3 Install a Desktop System

After power-on, the screen will remain on the logo display state. To install a desktop system, refer to the document《应Application Notes / Installing a Desktop System.》

3.4 UI Application Development

For UI application development, follow the instructions in the document 《EASY-EAI-Solution (Development Examples) / QT GUI Examples.》