Realtek 8188 wireless breakout/dautghterboard
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Realtek 8188 wireless breakout/dautghterboard

by walker on Wed Mar 06, 2013 2:17 pm

My wife's cheap android tablet died a while ago and due to the truly bad touchscreen it's passing was not mourned. However I did celebrate its disassembly to recover parts that might fit into future arduino projects.

One of the things I found was a small sort of breakout board that contains a Realtek 8188 chip. The board bears an Ostar manufacturer name. It has 4 pigtail wires that are nicely labeled in the silkscreen. I'm wondering if there is anywhere that I can get info about this board. I'm not having much luck with Google searches. Is this something that could usefully be interfaced to an Arduino? Or do these chips typically require a lot of driver overhead that would be difficult to do in a microcontroller platform?

I would think about playing with it on my Rpi but frankly it's just easier to use a USB adapter on that platform.
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Re: Realtek 8188 wireless breakout/dautghterboard

by adafruit_support_rick on Wed Mar 06, 2013 3:59 pm

If its a resistive touchscreen, it essentially has two resistive networks, one for X and one for Y. The 4 leads may be +X, -X, +Y, -Y.
Our resistive touchscreen reads around 300 ohms across X or Y without a touch. Touches will change the resistance.
You might play around with a multimeter or scope and see what you can figure out.

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Re: Realtek 8188 wireless breakout/dautghterboard

by walker on Wed Mar 06, 2013 5:29 pm

That is an excellent answer but unfortunately not to the question I asked. ;-)

I'm actually asking about the Realtek wireless duaghterboard that I pulled out of that tablet.

But your answer wasn't wasted. Indeed there was a resistive touch screen removed from the tablet (and saved) and it did have 4 wires. I know very little about how touch screens work but now you've got my interest piqued and I may have to pull that out and play with it.
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Re: Realtek 8188 wireless breakout/dautghterboard

by walker on Fri Mar 08, 2013 11:59 am

I'm hoping a photo might help. Here is the unit. If anyone knows how to find info about it or has any kind of advice about how to reverse engineer it let me know.
Attachments
ostar_realtek..jpg
ostar_realtek..jpg (67.72 KiB) Viewed 313 times
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Re: Realtek 8188 wireless breakout/dautghterboard

by walker on Fri Mar 08, 2013 1:23 pm

The leads that you can see attached are labeled V++, U-, U+, and GND. VCC and GND are easy enough to understand but the U+ and U- notations are not something I've seen before.

There are also two unattached terminals on the same end labeled LED, and WPS.
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Re: Realtek 8188 wireless breakout/dautghterboard

by adafruit_support_bill on Fri Mar 08, 2013 2:02 pm

The RealTek site says the chip has a USB-2.0 interface. Perhaps those are the D+/D- lines.
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Re: Realtek 8188 wireless breakout/dautghterboard

by walker on Fri Mar 08, 2013 9:52 pm

That would make sense.
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