Development of an adapter board design for Kosagi Novena LVDS interface to connect to the "iPad 3" QXGA 2048x1536 eDP LCD panel (aka LG LP097QX1-SPC1 and related models). Possibly also a touch screen interface to suit that display...
INITIAL PROTOTYPE STAGE, NOT A THING YET
Very closely modelled on Bunnie's existing Novena eDP adapter, with additions. LVDS connection cable from Novena should be the same on both boards.
Designed using KiCad (2014-07-25, any recent version should be OK to open the files). Gerbers are available from the releases page.
- Backlight driver (2x TI TPS61181)
- Touch screen controller Focaltech FT5816LPC with i2c and USB interfaces. There's a strong chance this will never work (lack of public documentation on controller or digitizer).
- 4 eDP lanes out of IT6251 eDP converter instead of the 2 used on Novena eDP board.
- Has a lot of numbered test points and 0R resistors due to undocumented or unknown factors.
- Has cut trace jumpers for some key power connections, can be cut to measure power consumption.
4 layer board, 1oz copper (35um). Desired stackup is:
- Front copper
- 0.2mm prepreg
- GND (Inner1)
- 1.2mm prepreg
- VCC (Inner2)
- 0.2mm prepreg
- Back
(This matches standard 4 layer stackup for my usual prototype PCB supplier, Hackvana).)
The 100 ohm differential microstrip traces (LVDS, eDP) are routed as 0.2mm trace / 0.15mm spacing (~8/6 imperial), at least where possible. This yields estimates in the range of 99.5-102ohm differential impedance depending on who you ask (assuming Er 4.4, calculated using TNT Field Solver and Jean Nicolle's impedance calculator.
Yay OSHW!
- http://emerythacks.blogspot.com.au/2013/04/connecting-ipad-retina-lcd-to-pc.html
- http://mikesmods.com/mm-wp/?s=ipad+3
You know a chip is going to be fun when photos of PCBs that use it become a useful resource to complement the datasheet.