Saturday, July 20, 2013

LP097QX1-SPA2 (iPad 3/4 LCD panel) teardown

Since I started making 2048x1536 LCD adapter boards, I have to test each one to make sure its working before sending out. One of the boards, the FPC connector wasn't aligned correctly during placement and during reflow it jumped one pin over. I didn't notice that and plugged stuff in, smoking the backlight traces and shorting panel VCC. I've always wanted to see what makes the panel tick, so I decided to take it apart. Results below.
Full-size pictures are in Picasa album, I can't figure out how to link them directly:

Obviously  working panel
Shields removed
A - EDID eeprom
B - ParadeTech DP635 T-CON
C - Couple DC/DC converters
D - Unknown use i7990 chip
E - Hiding behind metal shield is A2=EE chip
F - Backlight connector
EDID eeprom access, maybe someone wants to change "Color LCD" monitor text
Backlight strips, one on top one on bottom of panel
A - 3A, 32V Fuse
B - Backlight connectors, Hirose
Some stickers on backlight Wooree LED
Unknown A2=EE R1R chip hiding under the metal shield. Certainly looks like a DC/DC converter because of nearby coils but there's already 2 of those near the center of the board... Could be custom Apple or LG junk.
For those who are thinking of using this panel for a DIY projector - with a lot of careful peeling, its relatively easy to extract the panel and driver board from its casing and disconnect backlight. After I noticed the connector was off by one (and of course after I thoroughly disassembled the panel), I decided to hook it up to a working driver board, and to my surprise, it actually worked:

Wednesday, April 24, 2013

iPad 3 retina display adapter to DisplayPort

I made this sometime last year but was too lazy to do anything with it.

UPDATE 12/24/2013 These are more or less regularly available in my rc junk shoppe. When not in stock, I'm either out of parts, or waiting for parts, or too lazy to make more.

It allows connecting LG's LP097QX1-SPA1 (or Samsung equivalent LTL097QL01-W01) to any PC/Mac with Displayport. I also prototyped a HDMI version (using HDMI>DP chipset) but it was huge (the chips involved are like 200+pins tqfp) and I don't really care about HDMI. Also HDMI would need v1.3 transmitter to do over 1080p and some cheap trash sources (LIKE EVERYONES FAVORITE HYPEBERRY PI) probably can't even do that. So sorry, no 2k screens on your $30 Lunix trash. It is USB bus powered (out of spec), drawing something like 800mA. This hasn't stopped anyone else from making stuff drawing ~1A from USB so I don't think this is an issue.

I got a bunch of unpopulated boards left over and firmware is half-assed - but with STM32F103CB on there, it can do pretty much whatever, including brightness control over USB, soft power on/off (panel logic/backlight power is separate switching regulators from MCU), or whatever. I have no interest in touchpanels or anything tablet related, so this is not something I would ever consider.

The board is made to be mounted with top-activated or side-activated pushbuttons (top-activated would be mounted behind the board) and is made so it ends up in upper right corner of the LCD panel, with both buttons and DP/USB connectors slightly behind the bezel. I was going to make a milled aluminum case and properly mount the board but got too lazy and didn't even get that far. So I just have the bezel and adapter sitting behind it.

It enumerates on PC as "Apple Color LCD" for EDID, and supports 2048x1536 @ 60Hz. With my HDMI prototype, I was able to set up EDIDs so that it properly centered 1080p stuff with black borders, or stretched it to 2048xwhatever (with black borders on top/bottom). Also note, eDP in this panel does NOT support HDCP. It did support HDCP when doing HDMI>DP conversion.

If people want these, drop me a note, if there's enough interest I'll assemble some.
Preference given to people who want these because of STM32 on the board and not the usual tarduino code copypasters.

Monday, April 1, 2013

The open sores mentality

the open sores mentality is not to create shit that works,
it's just to create shit.