How setup LTDC to DE MODE

[uilter]

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.

 

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

Thanks for any tip and help!

[ktrofimo]

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

[uilter]

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

This is the timming table

 

Resumed pinout: note there is not VSYNC and HSYNC

Then my CubeMX setup (My LTDC clock is 25MHz):

 

Let me know if you need more informations.

Thanks.

[ktrofimo]

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.

[INaee.1]

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

[uilter]

Hi @Community member​ 

Thanks fot your comment.

When you sad "put the value 1 for each i-e VSync =1 & HSync = 1 in CubeMX" is set the polarity in LTDC configuration to Active HIGH or set the GPIOs to output and config it to HIGH state?

Thanks.

[INaee.1]

Hi

my experience is ....

You can't disable the LTDC essential signals and set as gpio output , if you do so then whole LTDC becomes inactive in cubemx.

 

The Vsync & Hsync signals can be disabled by putting value 1 for each , as I mentioned before and practically observed.

 

BTW .. my most recent TouchGFX experiment with custom designed board is across STM32H745XIT6 Core board with 1024X600 Chinese TFT .

The above board is with multiple communication protocols . and this customized board is based on following Core Board.

 

I also implemented Modbus Master RTU with TouchGFX on my previous development board.

Simulated the Modbus values from ModBusSlave utility on laptop and observed values on TouchGFX in numeric figures , custom guages & vertical bars.

 

 

thanks

 

 

[INaee.1]

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 ..

[uilter]

In this custom board I also is with another two displays:

• 7inch 1024X600
• 10.1inch 1024X600

Next step I will design a RGB->LVDS bridge to a bigger display with high resolution (1280x800).

In another custom board I put a RGB->HDMI bridge. I not test it yet.

[INaee.1]

Hi ..

Here is TouchGFX running on HP S1932 18.5" Monitor's LVDS LCD with 1366x768 resolution .

The lcd part no. is LTM185AT04 or Equivalent . The driver is stm32f429i-discovery + sn75lvds83b  

BTW ,, I tested ThinkPad T400 TFT 1280x800 resolution with my RGB>LVDS and working fine.

[ktrofimo]

About 10 years ago I have tested RGB->HDMI bridge (I believe it was from TI) and it was working fine in HD mode (720p) because STM32F429 was too slow for FHD (1080p). But RGB->CVBS (Analog Devices, composite TV) bridge test failed because I was unable to output 27MHz clock (doubled and sync'ed with pixelclock 13,5MHz)

[uilter]

FYI

I'm using the TFP410PAP from TI for RGB-HDMI bridge.

[Shashikant_Hiremath]

I tried adjusting display settings and display works!.