Bryan Hurley wrote:
> I got one of the Earth LCD 6.4" kits (used) and it works....
That the same LCD I use.
> but there is flickering.. just a slow two lines of distortion that go up
> the screen then again .... I am assuming this is something to do
> with the VGA->LCD controller that is with this display..
You are generating an analog signal and converting to digital.
>From the silicon imaging web site ...
Digital monitors—such as desktop LCDs—require an analog
signal to be converted back to digital form. This adds cost to the
monitor, and additional image data can be lost in the process. It
is particularly difficult to translate analog data to control specific
pixels on the screen; if the conversion of the sync signal is not
perfect, you can get annoying pixel-jitter defects as interpolation
causes the image to shift back and forth.
By contrast, a digital interface can take the digital data directly
from the computer and display it pixel-for-pixel on a digital display.
The result is a rock-steady image, and the screen receives every
bit of the original color information.
http://www.siliconimaging.com/dvi.htm
WIth direct connection from PCM-5822 LCD header, I get a rock
steady and very crisp image, no flicker.
> I was planning on getting a 5822 and was wondering, this should
> work fine and be even crisper when driven directly all digital from
> that board right?
Yes. Note however that I did see flicker on my first three attempts
to make a cable for NL6448AC20-06. I first followed the Advantech
pinouts for this display, and they put all of the ground lines on one
pin, that caused flicker. By moving the ground signals so each
has a separate pin, the flicker went away.
It seems that different graphics controllers have different levels
of tolerance for noise and attenuation. I used this same display
on two different Cell Computing (now PFU systems) boards and
I could run longer cable lengths without flicker.
Check to see that the hirose connectors are tightly seated on the
LCD end and also on the A/D converter board. It might be worth
unplugging them and plugging them back in. I hope the cable is
not longer than 18 inches because that's about as far as you can
go without using another interface like LVDS or PanelLink. But
you don't want to carry that A/D converter board anywyas, so
skip the analog altogether and wire it up like this:
NL6448AC20-06 PCM-5822
1 3 GND
2 35 SHFCLK
3 38 HSYNC
4 36 VSYNC
5 4 GND
6 27 RED0
7 28 RED1
8 29 RED2
9 30 RED3
10 31 RED4
11 32 RED5
12 8 GND
13 19 GREEN0
14 20 GREEN1
15 21 GREEN2
16 22 GREEN3
17 23 GREEN4
18 24 GREEN5
19 33 GND
20 11 BLUE0
21 12 BLUE1
22 13 BLUE2
23 14 BLUE3
24 15 BLUE4
25 16 BLUE5
26 34 GND
27 37 DATA ENABLE
28 5 VCC 5V
29 5 VCC 5V
30 NC NO CONNECT
31 39 GND
I used to have an extra connector on the LCD wire, it was a FDD
cable male and female combo, and I installed it in my jacket
pocket. That way I could just plug the LCD into the header in my
pocket and it worked great. It also distributed power to the LCD
and was hot swappable. But for some reason this does not work
with PCM-5822. Whenever I add an extra connector, I get flicker.
Seems the cell graphics controllers worked differently, perhaps
they had stronger or cleaner signals.
-- Doug
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