H747 DSI use one data lane issue

[SONGTAOSI]

First, let's introduce the usage environment.The Board is STM32H747I-DISCO, the LCD board is MB1166-A09,and the pack is STM32Cube_FW_H7_V1.11.0.

Now I'll describe my issue. In the official routine LCD_DSI_CmdMode_SingleBuffer, DSI uses two data lanes to communicate with the display, and the display can be displayed correctly.Now I want to use one data lane to communicate with the display, the LCD do not show anything.I made the following changes to the official routine：

OTM8009A is driver IC of LCD(MB1166-A09), and have a pin LANSEL to select one  or  two data lanes communicate with MCU. However I unable to find the LANSEL pin pad . Does that mean users cannot change two data lanes to one data lane of LCD side？I want to know how to achieve DSI communicate with the LCD (MB1166-A09) with one data lane.

Looking forward to your reply！

[SONGTAOSI]

Could anyone help me solve this problem?

Thanks!

[MOBEJ]

Hello @SONGTAOSI 

Since you are operating in command mode, you can indeed run the same example (CD_DSI_CmdMode_SingleBuffer)  from the STM32H747I-DISCO using 1 data lane. To achieve this, you need to disable the High-Speed mode and ensure that the display refresh operation is performed in LP (Low Power) mode. The MIPI DSI standard allows for operations using only one lane in LP mode.

For your convenience, we have attached the modified main.c file. In this file, we have configured the system to use a single lane mode and set the commands to operate in LP mode. This should enable communication with your LCD (MB1166-A09) using a single data lane.

Br

[SONGTAOSI]

Thank you for your reply，MOBEJ!

Your reply has been of great help to me. However, according to the description in the reference manual, single data lane is also supported in high-speed mode. So I would like to know if the hardware configuration at the LCD side（LANSEL pin set to 1） needs to be modified?