how to get the 7" LTDC to work with stm32h743ii on a waveshare board?

[Tesla DeLorean]

Get the screen geometry and timing correct.

The timing is frequently dependent on the resolution, not the physical size.

[WBeck.1]

Yes I understand that, thank you for answering. I am trying to start a project in touchGFX and I can not find a demo or example for a STM32H743II.

[ktrofimo]

Question is - what display model you are using and what touch IC it has. You will need datasheets for both of them.

Display datasheet will give you timing information for LTDC (screen viewable pixels, pixelclock, FP, BP).

For Touch IC you will need to use either existing driver (if you are lucky) or write your own having some driver as an example and implement data communication (usually over I2C or SPI) according manufacturer datasheet. Please note that some touch ICs have only linux open source driver and then you will need to port it to STM.

[KMacf.1]

Actually, I don't think you need front & back porch lengths in terms of number of pixel clocks any more - LCD seem to have got smarter & are more tolerant of the Hsync & Vsync pulse FP & BP lengths. As long as there's an Hsync & a Vsync, that's sufficient.