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> C1000,c3xxx Stereo In, Internal Mic, Wifi, Bt, ...from angstrom mailing list
speculatrix
post May 13 2008, 11:32 PM
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some discussion of hardware hacks came up on the angstrom user's mailing list* so I thought people here would be interested.

It began with an off-the-cuff remark by Stanislav Brebec about stereo audio input, I asked for more information. he explained that the Zaurus x000 series are capable of stereo sound input, it's just that Sharp decided to ground one of the inputs, here's the HOW-TO

http://lists.linuxtogo.org/pipermail/angst...May/001888.html

that message also goes on to discuss internal microphone, wifi and bluetooth - click on the "next message in thread" to see the follow-ons.

the hardware discussion then carries on in this thread:
http://lists.linuxtogo.org/pipermail/angst...May/001892.html


* I am not on the dev's list as I got fed up with the bitching
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pelrun
post May 14 2008, 03:59 AM
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Well, first things first, RINPUT1 is not just tied to ground; it's connected to pin 2 on the jack. I don't think it's a "historical" leftover or anything - smartest thing to do is to look at eviljazz's driver source to see exactly what is being done with that signal. (headphone/microphone detection perhaps?)

Easier to target RINPUT2/LINPUT2 (pins 25/26 on the chip) anyway - they are not connected to anything on the schematic, and the pictures of the board only show a couple of stub traces covered by solder mask, no vias. Since the chip pins are accessible and larger than those traces, it's probably easiest just to solder straight to them.
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utx
post May 14 2008, 04:36 AM
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QUOTE(pelrun @ May 14 2008, 01:59 PM) *
Well, first things first, RINPUT1 is not just tied to ground; it's connected to pin 2 on the jack. I don't think it's a "historical" leftover or anything - smartest thing to do is to look at eviljazz's driver source to see exactly what is being done with that signal.


RINPUT1 is not connected to pin 2 directly, but via a coil (which could be removed).

I have been experimenting with this signal a lot. The result is the latest alsa-state package in oe.dev, which uses RINPUT1 for the semi-differential mono input. (It is grounded, so it is not a real differential input.) In theory it could give better signal/noise ratio. In practice, I hear no difference. Z seems to be well wired.

I have no idea which WM8750 driver was written by eviljazz. Could you be more specific?

QUOTE(pelrun @ May 14 2008, 01:59 PM) *
Easier to target RINPUT2/LINPUT2 (pins 25/26 on the chip) anyway - they are not connected to anything on the schematic, and the pictures of the board only show a couple of stub traces covered by conformal coat, no vias. Since the chip pins are accessible and larger than those traces, it's probably easiest just to solder straight to them.


It would be much better to use RINPUT1 - all needed parts (capacitors, PCB traces) are already present there, and the device will remain compatible with unmodified Zaurus.

RINPUT2 and LINPUT2 are wired on the top side to a metalized holes and then traces continue on the reverse side of PCB. I don't have needed photos to trace them yet.
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pelrun
post May 14 2008, 06:48 AM
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QUOTE(utx @ May 14 2008, 10:36 PM) *
RINPUT2 and LINPUT2 are wired on the top side to a metalized holes and then traces continue on the reverse side of PCB. I don't have needed photos to trace them yet.


Ok, I was wrong, those points do go to vias, but they only go to the next layer down, not the other side of the board (full depth vias are bigger.) However the only place they eventually go to are test points N501 and N502; the schematic is specific. No, I don't know where those points are, nothing I have gives a physical location of the test points. For all I know they're under the CF connector... tongue.gif

You're free to pursue your option, of course; I just know what route I'll be taking when I get around to doing this mod myself (I investigated it a long time ago, actually - but only just got brave enough to open my Z a couple days ago biggrin.gif )
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