FoxyRick
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tft lcd panel connectors
Hi all,
I'm trying to get an LP121S1 LCD panel from LG, 800x600 18-bit TFT, to interface to a single-board computer with a CT69000 display chip.
Does anyone have any experience doing anything similar? Especially with regard to cable screening?
The chip supports the basic type, and I have eventually been able to get an almost perfect picture, but:
only by wrapping tinfoil around several wires, then the whole set, then connecting that to ground at one end only. Even now, the display is a bit jittery and really breaks up if I try to display a high-contrast image (like a black+white menu)
The connection is a standard 40-way ribbon cable, with a 44-pin idc socket on one end for the SBC, the other end soldered to a small home-made PCB with a hirose socket on it. This plugs into the LCD.
If I touch the foil shield, sometimes it gets better, sometimes it gets worse. I did try replacing the shfclk and M/DE lines with proper shielded cable, this would not give any display whatsoever.
Playing with the foil screening makes massive differences, and to me they do not always make sense. Properly screening the clocks did not work, twisting the cable together and wrapping my hands around it was better. The tinfoil nearly works but is not really practical, even if it was perfect.
What do I screen and how? where do I ground it? I've been playing with this for my entire week off work - it still is not good enough. Arggg!!!
Edit: I forgot - I also had to add a small inductor (no idea value) in the shfclk line to get the display stable. Not sure if the chip's timing is slightly off, or just another screening/grounding artifact
Hi all,
I'm trying to get an LP121S1 LCD panel from LG, 800x600 18-bit TFT, to interface to a single-board computer with a CT69000 display chip.
Does anyone have any experience doing anything similar? Especially with regard to cable screening?
The chip supports the basic type, and I have eventually been able to get an almost perfect picture, but:
only by wrapping tinfoil around several wires, then the whole set, then connecting that to ground at one end only. Even now, the display is a bit jittery and really breaks up if I try to display a high-contrast image (like a black+white menu)
The connection is a standard 40-way ribbon cable, with a 44-pin idc socket on one end for the SBC, the other end soldered to a small home-made PCB with a hirose socket on it. This plugs into the LCD.
If I touch the foil shield, sometimes it gets better, sometimes it gets worse. I did try replacing the shfclk and M/DE lines with proper shielded cable, this would not give any display whatsoever.
Playing with the foil screening makes massive differences, and to me they do not always make sense. Properly screening the clocks did not work, twisting the cable together and wrapping my hands around it was better. The tinfoil nearly works but is not really practical, even if it was perfect.
What do I screen and how? where do I ground it? I've been playing with this for my entire week off work - it still is not good enough. Arggg!!!
Edit: I forgot - I also had to add a small inductor (no idea value) in the shfclk line to get the display stable. Not sure if the chip's timing is slightly off, or just another screening/grounding artifact