in electronic ~ read.

Asus ME571K aka Nexus 7 (2nd gen) touch digitizer reverse engineering (pinouts)

In 1st part I've described a bit history between 1st and 2nd gen and why I'm going to look more at 2nd generation of Nexus 7.

Spare Nexus 7 came from eBay (also ordered plain digitizer for testing) and I need to say very easy to get into  internals but will not bother you with boring tear-down and will start focusing on sub board where touch IC and connectors are.

Image of disassembled sub board from Nexus 7 and marked RED is part that we are interested(Touch IC eKTH3258AWS) to get pin-outs as TPCON1 and TPCON2 are connected to it.

And image from digitizer that goes to both of TPCON connectors



Image from digitizer is taken so when you look into board match exactly and yes connectors are TOP  so when I was looking for matching connector was really challenging. At end I have found 2 connectors that match
- Molex 502598-3393 (ordered Molex as is easier to get it)
- FH35C-33S-0.3SHW(50)

And now finally time to removed Elan eKTH3258AWS and both TPCON to get exposed pins and easier to work with probe while doing pin mapping.

TPCON removed
Elan eKTH3258AWS removed

After a long search for datasheet was impossible to get any details but managed to get pinouts from one vendor on AliExpress :)

Elan eKTH3258AWS Pinouts

Now after I have all pieces now was only matter of time until I get pins right. This is my initial pin mappings (and I know it's lame to make it like this but was easy)

TPCON1 pinout
TPCON2 pinout

As you can see from images we have 36TX and 22RX one interesting part that I still didn't figure it out is Pin 2 on TPCON1 and Pin 32 on TPCON2. I have marked them as ? as they are floating (didn't find any pins or board connected to that 2 pins). Will be interesting to find out for what are they and will I need them later on...

And question is what to use for next step, which touch IC to find and use. For sure I don't wanna use Elan as they can't be bought easily but there is a lot others (FocalTech, Synaptic, SiS, Illitek...)