Troubleshooting LTDC

[GK28]

Hello,

I am developing a GUI application with TouchGFX which I would like to run on a STM32F767ZI connected via LTDC to a display with RGB888 interface.

The display datasheet: https://newhavendisplay.com/content/specs/NHD-5.0-800480AF-ASXP.pdf

I am having problems with the configuration in CubeMX. I followed the guide in AN4861 to configure the LTDC but I am still having problems.

With my current configuration, when I set the background for the LTDC to red, and the Layer 1 to transparent (alpha = 0), I can see that the display correctly displays a red background.

When I set the Layer 1 to opaque (alpha = 255) with a red background, the display always shows a black background with a TV static like white rectangle on the top of the screen. It doesn't matter if I added TouchGFX as a Middleware or not, it always displays the same thing.

Current configuration attached.

Thanks in advance for the help!

[GK28]

I am inserting the attached photos directly. I added a picture of the screen with a static rectangle when the layer 1 is enabled and a picture of the background for the LTDC working currently when layer 1 is set to transparent.

LTDC configuration

LTDC configurationLTDC pins

Static rectangle with Layer 1 enabledBackground works with layer 1 set to transparent

[GK28 · Accepted solution]

Hello,

here is my solution, may it help future developers:

How to show a static image on the display

The image is converted with the newest version of the LCD-Image-Converter-20161012 tool (as indicated in "Introduction to LCD-TFT display controller (LTDC) on STM32 MCUs", AN4861, 7.2.4 - 7.2.5).

In the LTCD options the Framebuffer pixel format is set to RGB565. The Preset in the LDC image converter has to be set to RGB565 as well, even if the display has a RGB888 interface. Otherwise the image won't be displayed correctly.

See Figure 48. and Figure 51. in the LTDC guide to see the configuration.

Good luck!