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ATank.1
Associate III
January 31, 2023
Question

Text not displaying properly in RGB 888 mode with STM32H745

  • January 31, 2023
  • 3 replies
  • 3184 views

I am using STM32H745 with 16bit SDRAM and QSPI nor flash for images and TouchGFX for developing the screens. Am using 800x480 resolution.

I have developed some sample screens which look fine when 565 color mode is configured in LTDC and DMA2D and TouchGFX.

But when I configure the application to use 888 color mode I see some texts not displaying properly. Please see attached images.

Also if you see the slider in the image it leaves a trail when moved till end and back.

I think some screen refreshing issue is present in 888 color mode.

What could be the issue here. Is this due to bandwidth issues with SDRAM / LTDC

LCD is running at 29MHz as per calculation and SDRAM is runnining at 100MHz

I tried reducing the LCD clock or also increasing the clock but issue persists.

Thanks

Anuj

This topic has been closed for replies.

3 replies

MM..1
Chief III
January 31, 2023

tgfx version ? know bug ...

ATank.1
ATank.1Author
Associate III
January 31, 2023

Thanks for the quick reply

TouchGFX version used is latest which is 4.21

MM..1
Chief III
January 31, 2023

Compare with older

Osman SOYKURT
Technical Moderator
February 2, 2023

Hello ATank.1,

Your issue remined me this thread. Do you also work with L8 formats ?

By the way, which complier do you use ?

/Osman

Osman SOYKURTST Software Developer | TouchGFX
ATank.1
ATank.1Author
Associate III
February 2, 2023

Thanks for the reply

Am using STM32Cube IDE with default STM32 GNU toolchain (GCC compilier)

Am not using L8 formats at all. only use 565 or 888 configuration in CubeMX and TouchGFX Designer.

My texts are not cut but are not displayed clearly and observed with only some texts and slider Observe this issue only with 888 format and not 565 format.

Plan to verify with previous version of TouchGFX.

Thanks

Anuj

Osman SOYKURT
Technical Moderator
February 6, 2023

Hello ATank.1,

I've tried with a STM32H745-disco TBS and changed the Framebuffer Pixel Format to use RGB888 instead of RGB565. Couldn't reproduce the issue.

Do you use double buffering for framebuffer strategy ?

/Osman

Osman SOYKURTST Software Developer | TouchGFX