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Author Topic: Tang Nano 1K/4K/9K connecting LVDS LCD?  (Read 524 times)

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Offline up8051

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Tang Nano 1K/4K/9K connecting LVDS LCD?
« on: June 27, 2022, 09:21:16 pm »
Hi,

I am trying to connect a laptop display to one of these modules TangNano /4k/9k.

LCD:
 - 1366X768
 - color 3x6bit
 - clock 76.8MHz/268,750 MHz (readed from EDID EEPROM)

The code is based on "GOWIN LVDS71 LCD reference design".

The first attempt of Tang Nano:
Because GW1NR-1LV does not have true LVDS ports and none of the banks on this module is powered by 2.5V, I decided to use external transmitters DS90LV047ATM.
Unfortunately, only half of the success: color bar and net grid are displayed correctly but gray scale (color change every pixel) is no longer displayed, the entire image is distorted.
This could be because the transmitter is too slow ( DS90LV047ATM - Max switching frequency Min:200MHZ Typical:250Mhz)

The second attemnpt TangNano 4k
We have a Bank-2 powered by 2.5V and true LVDS output but this time nothing is displayed correctly.
Of course I remaped outputs and configre PLL respectively for GW1NSR-4C.
I think the problem is that the lines are used for HDMI interface (the lines are loaded by serial capacitors C2-C9 and pull-down resistor R1-R8).
Unfortunately, these elements are so small that when I desolder them, I will not mount them again and I only have one 4k module.

Tang Nano 9k again no 2.5V I/O Bank.

Any idea how to connect LVDS LCD to Tang Nano or some other FPGA modules with such a possibility?

BR JarekC






 

Offline mon2

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  • Country: ca
Re: Tang Nano 1K/4K/9K connecting LVDS LCD?
« Reply #1 on: June 29, 2022, 10:00:27 pm »
I would study the Gowin video kit (believe it is the proper one) which features an external FPC cable going to a local LCD. That kit documentation and IP should be a good start for such a project.
 


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