Flickering issues with TouchGFX running a 7in 800x480 display

[YTalh.1]

Hello,

I have made a custom board based around the STM32F746IGT6 MCU to run a 800x480 display 7in (4DLCD-70800480). I am using external FLASH (MT25QL128ABA1ESE-0SIT) and external SDRAM (AS4C4M16SA-6TIN).

I have ran into two main issues so far:

• The display seems to be flickering at random times, as shown in the first video below (this does not always happen, which makes me think it could be a layout or hardware issue, as I did assemble the board myself). Do you guys have any guidance as what kind of issue could cause this flickering? Could this be a LTDC issue? Here is the video: https://youtu.be/-qseq_30Y88
• When running animations, there seems to be some "weird" behavior: wrong colors being displayed, and the animated image shifts a few pixels back and forth. From what I read, this seems to be related to SDRAM. I am only using single buffer, as things actually get much worst in double buffer mode, which tells me that my SDRAM might not be setup properly. However, I did implement the SDRAM example from the STM32F746 DISCOVERY BOARD on my custom board, and I am able to write and read to the SDRAM, so I am not completely sure why I cannot get the SDRAM to work in double buffer mode (first buffer at address 0xC0000000, second buffer at address 0xC0119400). Here is the animation video: https://youtu.be/TQ5T-l4oDZU

Here is the layout:

Here are my clock settings: 

Any help or guidance is greatly appreciated.

Thank you.

[MM..1]

I see here more trouble

• you show LTDC clock 33 for example for 50Hz you need around 22MHz
• your pcb seems be 2 layer
• SDRAM traces isnt lenght compensated
• for double buffering is recomm start address on bank start for example 0xC02000000
• memory is 166MHz then try set MCU clock optimized for this

For test i recomm configure buffer to internal sdram and test ltdc ffunctionality without sdram.

[JLee.32]

d

[JLee.32]

@YTalh.1 (Community Member)​ Did you solve these issues? If so, can you share how to solve?

[Zakba.1]

Hi

could you solve it? would plz chare the solution?