MIPI DSI not working on STM32U5

Charlie CHEN · ‎2025-04-29

Hi,

I have an issue on MIPI Display with our custom board, information as below,

Reference example : STM32Cube_FW_U5_V1.6.0\ STM32U5x9J-DK\ DSI_VideoMode_SingleBuffer

I have noticed that example code is the same MIPI command and also LTDC timing as mine.

And I set as the same ,but still not display anything. So I checked few things,

DSI_Dn/Dp signal in scope are the same polarity (It should be differential signal)
> PCB layout & Schematic both design in correct. And Dn/Dp is in correct impedance.
> There is a saying, no display or Black will show the same polarity, is it correct?
In example code, there are two different CMD(SetPanelConfig, mipi_config).
> After set with mipi_config, there is no change on display and same polarity.
> After set with SetPanelConfig, display appear stripe but same polarity.

If it is correct of my understanding, LP mode is for CMD configuration on level ~1.2V, HS mode is in data transfer for display on level ~200mV.

But as my measure, either same polarity or always on level 1.2V.

Is there anything I missed?

Any help will be appreciate~

Thanks.

Charlie CHEN · ‎2025-05-04

Hi,

Is there anyone can help?

Thanks.