Dear @MRobi
If the DSI functionality is not used in your STM32H747 MCU project, the DSI pins DSI_CKP, DSI_D0P, DSI_D1N, DSI_D0N, DSI_CKN, and DSI_D1P can be left unconnected. However, it is recommended to ground these pins to avoid potential issues such as increased power consumption.
As for the VDDDSI and VCAPDSI pins, they should not be left unconnected. The VDDDSI pin must be connected to the global VDD, and the VCAPDSI pin must be connected externally to VDD12DSI, but the external capacitor is not needed if DSI is not used. The VSSDSI pin must be grounded.
Cheers,
STOne-32 {Nova}