You need to distinguish between single pixel and double pixel LVDS interface (some refer to them as single - or double channel) and colour depth (6- or 8-bit).
I've noticed that there are Odd and Even pairs (pins) in LVDS connector in some DVI->LVDS boards. I've took a quick look on mentioned page, and there were some explanations.
Let's take the Nexus 7 as an example. Colour depth on the Gen1 display (the one that I have on hands) is 6-bit, that's why it has 3 differential signal pairs for data Y0 to Y2 (Y0 is the upper channel in the mapping charts and Y3 is the lower one).
Single- or dual pixel is (let's say most of the time, there are exceptions to this as well) related with the displays resolution: single pixel (channel) LVDS is possible up to HD (1366x768) pixel.
In addition to this it needs you need to have a differential signal pair for the clock signal.
I know, clock is one pair, that leave 5 pairs for data, I'm not really sure to think that there is 2 more pairs on those 4 wires in question, they are not in layout that suggest they can carry high frequency differential signals. Those tracks are right beside a power track (what else it can be - thick track that connect 2 pins in both connectors). Also there must be at least one track for backlight control - that's would leave 3 tracks....
Total price for the PCB is roughly USD40 with transportation cost being higher than actual PCB cost (USD12). They are HAL only: no need to spend anther USD26 for ENIG (since I'm just using them as proof-of-concept samples).
To me this looks like 8 differential signal pairs! The display is FHD resolution so it needs to be dual channel LVDS (odd and even channel) --> you will have 3 data channels and one clock channel for odd and even LVDS channel. This results in 8 differential signal pairs, but colour depth is 6bit only for this connection. Will be hard to tell what goes to where without having the displays data sheet...
Yeah, I know, as I've been looking at that web page most FHD (1920x1080/1200) panels had 8-pairs. While up to HDRedy (1366x768) had only 4 pairs (3+1). I'm really starting to think that the Nexus 7 2013 (gen2) LCD have 4-lane MIPI-DSI interface... Well, that is a killer :/ for my imagination...
I'll will wait, there might popup in near future somewhere ME571K repair guide/service manual or LCD datasheet for free download (so far I found ME571K for $$$$).
... build 1st sample ..
... and nearly there ..
Will you public your project (PCB designs, configurations, etc.) ?
I think I'll play for now with Gen1 LCD so I might bother you in future how you did it
As for Gen2 lcd, There is too much unknowns about it (for now).
--- EDIT ---
I just found out what interface is looking at /sys/class/graphics/fb0/.
The Nexus 7 2013 (aka Gen2) have MIPI-DSI interface. So I just wasted time :/ because it not possible for me to use it.
Code: Select all
[email protected]:/sys/class/graphics/fb0 $ ls
[email protected]:/sys/class/graphics/fb0 $ cat msm_fb_type
mipi dsi cmd panel
MIPI DSI - that's explain itself. So now I'm looking at N7 2012 LCDs