How to connect a LCD to STM32 through long distance(2 meters)

[snkparty1]

We are developing a user interface by using STM32H743 + SDRAM + LTDC + DMA2D and connecting to LCD through an FPC cable, which is only 30 CM long. It works fine.

But there is one problem, in some of our products, the LCD can be placed at a position that is 2 meters away from the control board. So I brought a 2-meter-long FPC cable, and the test result was quite bad. Images on LCD became quite unstable and the touch function totally broke down...

Is there any solution for this problem?

[CYANG.1]

Hi,

I think it is hard to ask a control microcontroller chip to have enough strength to support a LCD at so far place. If thus condition is happened,  relay chips in the middle of cables are needed.

B.R.

[Ozone]

That won't work.

Even for a proper cable with reasonable well adapted wave impedance, attenuation is proportional to length.
The very same reason why obtainable baudrates on RS232, CAN or SPI nets get lower the longer the cables become.

[snkparty1]

I tired to find a relay chip on the internet but found nothing. I wonder if rgb signal relay chip even exists?...

[snkparty1]

I did a little bit of digging and only found one solution that may or may not work. Use a rgb to HDMI transmitter chip to change rgb signal to HDMI, so the signal can be sent over a long distance. But we use a touch screen, so even if this works, another USB-C cable is required to transmit touch position information.

This is the only solution that seems to work...

[CYANG.1 · Accepted solution]

Hi,

CMOS signals are easy impacted by noises in its path when it is long. So it is better to guarantee the output signals are set with strongest driving ability in MCU side. And good shield is also recommended on its path.

But, the best way is to put MCU and LCD close to each other.

Best Regards.

[snkparty1]

I finally decided to use rgb to HDMI transmitter to transfer graphics and a USB to transfer the touch signal.  Thanks for the advice.