LVDS/FPD-Link Pinouts
This seems to come up often-enough, so maybe it's time I compile a list of my experiences...
In my experience, there are two common pinouts for each type of LVDS/FPD-Link connector... E.G. two common pinouts for the 20-pin connector, two for the 30-pin connector.
Most manufacturers seem to supply displays in these different pinouts. The model-numbers are usually the same, but they tend to contain a -# that indicates the pinout and other feature-differences.
E.G. The LTN121XJ may come in both these pinouts, the "-L02" may indicate *which*.
This information is compiled *long after* I last used it, so take it with a grain of salt. If you have any corrections/questions, don't hesitate to contact me!
Note some key differences between the two pinouts... Especially with the power/ground signals. So, if you have an unknown pinout, you can probably assume it's one of these, and determine *which* by using a multimeter's continuity-setting to "beep-out" the ground-signals, which are usually all connected together on both the display and the cable.
NOTE Some displays which don't contain EDID chips use other methods to indicate to the computer which display is connected. E.G. They might short-out two EDID pins, or short one to ground.
So, be wise and check those EDID-signals aren't shorted/grounded before hooking up your display to your computer!
Random notes:
RXin0 usually is "red", RXin1 is usually "green", and RXin2 is usually "blue/sync".
If you mix these up, you may see unexpected colors, or nothing if RXin2 isn't correct (since it contains the hsync/vsync and Data-Enable signals). It shouldn't harm your display if you get it wrong. Similarly, if you get the polarity wrong (wiring RXin0- on the display to TXout0+ on the cable) it shouldn't cause harm, but may cause color/sync issues.
See this document for "VESA" pinouts (Also has a 40-pin connector).
Also see the SPWG SPEC
If you want to understand the underlying signals... this is a good document, albeit a bit misleading as far as pinouts and accepted standards. There's similar and more-relevant info around this site.
Briefly: The FPD-Link "standard" was designed with expandability/compatibility in-mind... E.G. say you wish to connect an 8-bit-per-color display to a 6-bit-per-color source... The lowest bits of all colors are carried on the Rin3 signal-pair. So, by not connecting these, only the lowest color-bits will be lost.
Also: Some displays are dual-pixel, while others are single-pixel. This concept is described in more detail elsewhere on this site. Briefly: dual-pixel displays draw two pixels side-by-side at a time, thus there're two "channels" ("even" and "odd") containing simultaneous pixel-data. This can get a bit confusing. But I mention it here because: If you have a computer with a 30-pin connector, but its *cable* only has wires to the first 20 pins, your computer can only handle single-pixel data. Most displays aren't sophisticated enough to *determine* what data it's receiving and therefore have no ability to switch "modes"... And, as far as I'm aware, older versions of the EDID can't actually tell the computer whether to send dual or single pixel data. So... if you're replacing a display with another, you should be cautious.
20-pin:
IAXG01*
IAXG01A SPWG: Section 5.1
LTN121X1-L01* VESA:Table 4-1
LTN121X1-L02** N121X5-L03
e.g.: HV121P01-101 LTN121XJ-L02
------------------------------------------------------------
1 VDD_3V3 GND
2 VDD_3V3 VDD_3V3
3 GND VDD_3V3
4 GND EDID_3V3
5 Rin0- N/C
6 Rin0+ EDID_CLK
7 GND EDID_DATA
8 Rin1- Rin0-
9 Rin1+ Rin0+
10 GND GND
11 Rin2- Rin1-
12 Rin2+ Rin1+
13 GND GND
14 CLK_IN- Rin2-
15 CLK_IN+ Rin2+
16 GND GND
17 EDID_3V3 CLK_IN-
18 EDID_GND CLK_IN+
19 EDID_CLK GND
20 EDID_DATA GND
*NOTE: These displays don't have EDIDs
Pins 17/18 are N/C or "Reserved"
Pins 19/20 are GND
**NOTE: This display has an EDID, but pin18 EDID_GND is N/C
30-pin: SPWG: Section 5.1
VESA: Table 4-2 VESA: Table 4-3
e.g. LTD121KM2S*
-------------------------------------------------
1 GND GND
2 VDD_3V3 GND
3 VDD_3V3 VDD_3V3
4 EDID_3V3 VDD_3V3
5 N/C EDID_3V3
6 EDID_CLK EDID_CLK
7 EDID_DATA EDID_DATA
8 OddIn0- OddIn0-
9 OddIn0+ OddIn0+
10 GND OddIn1-
11 OddIn1- OddIn1+
12 OddIn1+ OddIn2-
13 GND OddIn2+
14 OddIn2- OddCLK-
15 OddIn2+ OddCLK+
16 GND GND
17 OddCLK- OddIn3-
18 OddCLK+ OddIn3+
19 GND EvenIn0-
20 EvenIn0- EvenIn0+
21 EvenIn0+ EvenIn1-
22 GND EvenIn1+
23 EvenIn1- EvenIn2-
24 EvenIn1+ EvenIn2+
25 GND EvenCLK-
26 EvenIn2- EvenCLK+
27 EvenIn2+ GND
28 GND EvenIn3-
29 EvenCLK- EvenIn3+
30 EvenCLK+ N/C
*NOTE: This display doesn't have an EDID
Most EDID signals are N/C, EXCEPT:
Its EDID_3V3 input is shorted to ground!
So, be sure to cut that wire!