Display flickering effect with TouchGFX on two different boards

[Southbranch]

Hi!

I got an external display RVT50HQTNWC00-B - Riverdi to work with TouchGFX, but only when showing static images/buttons. I am testing STM32H735G-DK and STM32H743I-EVAL in paralell. These boards are using OSPI HyperRAM and SDRAM respectively to store the framebuffer(s).

But for both boards I get the same severe flickering effect :\ when trying to update a simple progressbar every 500ms (see video). The two text areas and button are static objects...

I have read the AN4861 and especially page 37. It seems the LTDC FIFO overrun flag is set in every breakpoint in void LTDC_ER_IRQHandler(void) and I have tried/observed a few things:

• Display is (naturally) set to max frequency 25 MHz
• Same flickering problem with both boards
• Single vs double framebuffer has no effect
• DMA2D has no effect
• Using only one LTDC layer
• Using RGB565 instead of RGB888 gives somewhat less flickering (gives framebuffer line width to 64/128 bytes)

Futher more, I am not sure how these recommendations from AN4861 could be achieved:

-"Update the framebuffer content during the blanking period when the LTDC is not fetching".

-"Use the largest possible memory bus width 32-bit instead of 16- or 8-bit SDRAM/SRAM".

What else can I do..?

Thanks in advance for any hints

[Southbranch]

Answering my own post:

-Setting up a new project from sqratch in CubeMX made the trick :folded_hands: