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How setup LTDC to DE MODE

uilter
Senior

Hi,

My MCU is a STM32H753BIT6. This is a custom board that works fine with SYNC-MODE displays types.

I have a new display only works in DE MODE. It not requires the HSYNC or VSYNC signals.

Is there any way to configure LTDC peripheral and TouchGFX to work only in DE MODE? This is a communication image about this mode.


_legacyfs_online_stmicro_images_0693W00000bVejGQAS.png 

I disconnect physically the VSYNC/HSYNC signals and ground it to make sure.

Thanks for any tip and help!

1 ACCEPTED SOLUTION

Accepted Solutions

It works =)

I change the settings to:


_legacyfs_online_stmicro_images_0693W00000bVjksQAC.png 

Also I reconnect the VSYNC and HSYNC signals to LTDC peripheral. Without it the display keep dead.

Just after these modifications that I mentioned it worked.

I had some flickers in transaction screen and animation widgets, but reducing a little bit the LTDC_CLK it works well. (Fine tuning)

@ktrofimo​ thanks to help me with it.

View solution in original post

19 REPLIES 19
ktrofimo
Senior III

What is your display model? Do you have datasheet? I would start with comparing "hsync/vsync" and "de only" waveforms...

I can not upload the file here, just some prints.

This is the timming table


_legacyfs_online_stmicro_images_0693W00000bViUPQA0.png
_legacyfs_online_stmicro_images_0693W00000bViUZQA0.png 

Resumed pinout: note there is not VSYNC and HSYNC


_legacyfs_online_stmicro_images_0693W00000bViUoQAK.pngThen my CubeMX setup (My LTDC clock is 25MHz):


_legacyfs_online_stmicro_images_0693W00000bViV8QAK.png 

Let me know if you need more informations.

Thanks.

What about display model? According to information you posted here it should work as regular TFT just without HSYNC and VSYNC signals. If you can't publish document - just give a model and/or link to the datasheet.

They allow me to send the link of the display.

https://www.winstar.com.tw/products/tft-lcd/ips-tft/800x480-ips.html

It uses the ST7262 LCD Controller.

It works =)

I change the settings to:


_legacyfs_online_stmicro_images_0693W00000bVjksQAC.png 

Also I reconnect the VSYNC and HSYNC signals to LTDC peripheral. Without it the display keep dead.

Just after these modifications that I mentioned it worked.

I had some flickers in transaction screen and animation widgets, but reducing a little bit the LTDC_CLK it works well. (Fine tuning)

@ktrofimo​ thanks to help me with it.

Flickering is usually not an LTDC interface problem. Read TouchGFX documentation on cache and RAM banks

See a discussion at: https://community.st.com/s/question/0D53W00001Gl5lJSAR/stm32h743-weird-screen-flickering

Thanks about this advice. I already use cache and config the MPU, but I will double check it to make sure.

INaee.1
Associate III

Hi .

I am using both type of TFTs ( with VSync + HSync + DE ) and also DE mode only

you dont need to disconnect the connection of VSync & HSync for DE Mode.

Just put the value 1 for each i-e VSync =1 & HSync = 1 in CubeMX

these values always -1 of actual value , that means 1-1 = 0 >> DE Only Mode.

I hope this will work

BTW ,, my custom design board is across H745xit6 with 7inch RGB TFT of 1024X600 resolution and I am running TouchGFX very well on it.

Imran

INaee.1
Associate III

Moreover ,,

I am using touchGFX on following TFT resolutions

5inch 1280X720 .. RGB + Spi (Generic Chinese Cellphones)

7inch 800X480 .. RGB (Generic Chinese)

7inch 1024X600 .. RGB (Generic Chinese)

7inch 1024X600 .. LVDS (Samsung Tab3)

and many more from LCD Monitors (LVDS type TFTs )

1024X600

1280X800

etc ..