MIPI Video mode generate abnormal graphic occasionally.

[HPai.1]

We have produced lots of touch boards with STM32F769. However, we found that the panel will show abnormal graphics occasionally. Please refer to the images attached. They are wrong color(normally should be blue) and vertical shift. These abnormal phenomena cannot be reproduced by systematical operation. But they do occur occasionally. How can we prevent these phenomena?

The board employs external QSPI flash and external SDRAM. The LTDC clock rate is 27.428MHz and the DSI land byte is at 62.5MHz. Panel resolution is 800X480 and rotated by 90 degrees.

[MM..1]

Hi i see same issues and mean this is an sync trouble in LTDC vs DSI init sequence.

Im disapointed too , that STM dont test and explain video mode on DSI equiped devices.

[Yoann KLEIN]

Hello,

Can you please provide some additional information :

• Which version of TouchGFXDesigner are you using ?
• Which Framebuffer pixel format are you using ?

Did you already try to build and run a more basic project on those boards, for example with just a box and some images ? To see if the issue comes from the project or from something else.

/Yoann

[HPai.1]

Hi, Yoann,

Designer Version 4.16 is used.

And the frame buffer pixel format is RGB888.

We do have built a more basic project on the same board. But never found the same abnormal phenomenon.

However, we also found it hard to reproduce the abnormal situation with the production firmware(a lot more sophisticated one). They do not occur easily but they do occur.

Actually, we produced more than ten thousand pieces of these boards and put them in everyday use. In such extensive usage, we are able to see this abnormal situation.

This rare occurrence is particularly frustrating. Cause it's hard to observe and find the root cause.

/Hodge

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