Bongofish

Screen Tablet malarky => Tablet Conversion to USB => Topic started by: gordon13 on September 15, 2011, 04:30:38 PM



Title: Converting Wacom XD-0912-R from Serial to USB
Post by: gordon13 on September 15, 2011, 04:30:38 PM
Alright lets do this.
Firs things first, checking continuity according to the table made by Bernard:
http://forum.bongofish.co.uk/index.php?topic=1927.0

First thing I noticed, the boards are slightly different. TR1R on this board is on the right side of the serial connector (assuming the board is oriented like in the other thread I linked). Also the serial connector is the other way around. The pins are marked 10, to 1  from the left side as shown in the following pictures.

http://dl.dropbox.com/u/4249784/P1150946.JPG
http://dl.dropbox.com/u/4249784/P1150947.JPG

Also, serial driver chip connections doesnt seem to match the table in the other thread :/

Where to go from here? Is the circuit still similar enough that removing TR1R and IC2R going to work? Also, how do I work out which pins will need to be soldered to the teensy?



Title: Re: Converting Wacom XD-0912-R from Serial to USB
Post by: bernard on September 15, 2011, 05:06:35 PM
The important stuff to test is the DB9 connector pins to the serial driver chip pin.  The special internal connector we do not really care.

Let me put the important thing to test here:


             
  PC DB9  |  ADM202
 ---------+---------
  2 (RXD) |  14
  3 (TXD) |  13
  4 (DTR) |   8
  5 (GND) |
  6 (DSR) |   7
  7 (RTS) | R2R





Title: Re: Converting Wacom XD-0912-R from Serial to USB
Post by: gordon13 on September 15, 2011, 06:06:24 PM
Thanks for the clarification. That works! I was test on the internal connector and getting confused, when i realized db9 was the connector on the end of the cable, i felt stupid^^.
Anyway I wasnt sure what R2R was so I didnt check it, but I assume its fine.
Now I had a look at this thread:
http://forum.bongofish.co.uk/index.php?topic=1928.0

and it looks like the circuit is exactly the same. I guess the next step is to remove the serial chip and the transistor?


Title: Re: Converting Wacom XD-0912-R from Serial to USB
Post by: bernard on September 15, 2011, 06:20:04 PM
R2R stands for "Resistor #2 - seRial component" it might be the R02R on your board -- the marking is a little bit off -- near the internal connector (because of limited space, they often put markings a little bit away from the component, but you can always figure out which is which).  Maybe try the "checkpoint CP1" (there is a little arrow that points to a little round copper pad).  Try anything in that area -- we want to know if it  connects to the RTS pin. 


Title: Re: Converting Wacom XD-0912-R from Serial to USB
Post by: gordon13 on September 15, 2011, 06:26:38 PM
RTS pin connects to checkpoint 1.


Title: Re: Converting Wacom XD-0912-R from Serial to USB
Post by: bernard on September 15, 2011, 06:55:10 PM
ok, then it matches.  You can proceed to unsolder the serial driver and the TRansistor on the side.

Make sure your tablet was somehow working before destroying stuff.  Else we will ask ourself if it fails because of the patch or because it was broken to start with.

Now we have to plan how we are going to patch things exactly.  For example, getting ground from the various places we need to connect to ground.


Title: Re: Converting Wacom XD-0912-R from Serial to USB
Post by: gordon13 on September 16, 2011, 02:18:01 AM
Right thats done. I ripped the solder pads under the chip, so ill have to find somewhere else to solder the wires. Should be easy using multimeter.


Title: Re: Converting Wacom XD-0912-R from Serial to USB
Post by: bernard on September 16, 2011, 06:13:25 AM
ripped all solder pads???  yipes.  Please take a picture.


Title: Re: Converting Wacom XD-0912-R from Serial to USB
Post by: gordon13 on September 16, 2011, 01:15:03 PM
Oh no now youve got me worried!

http://dl.dropbox.com/u/4249784/P1150950.JPG
http://dl.dropbox.com/u/4249784/P1150951.JPG



Title: Re: Converting Wacom XD-0912-R from Serial to USB
Post by: bernard on September 16, 2011, 04:42:58 PM
I am just surprised how many you ripped.  Maybe your solder was too hot or you kept it too long.  Did you try to cut the legs before removing them?

We will find ways to fix this do not worry. Now try to be extra careful.  I do not have this exact board in my hand, so I cannot search for good soldering points myself.  You will have to do it yourself.  If none is available, then you will have to ***gently*** scratch the green compound on top of a trace to expose the metal.

First you need to find exactly which pins are required to be soldered (most of them must be kept unconnected).

Now for the 5V power regulator, you need to lift (of better: cut) one of the leg. You will then have to solder on the pad (or the little remaining leg piece).

Actually, you should solder the power (and ground) first and test that.  (the led must lit when playing with the pen).   When that works, you can look at soldering the serial signals.


Title: Re: Converting Wacom XD-0912-R from Serial to USB
Post by: gordon13 on September 16, 2011, 07:51:59 PM
I couldnt get rid of enough solder for it to come off easily so i forced a bit and didn't realise just how fragile the tracks are. I think the main problem is, i dont really have the best equipment. only a swiss army knife and a soldering iron with a flat 45 degree tip.

Alright so ive cut one of the legs of the regulator and soldered a wire on the pad. Ive also soldered a wire on the internal connector pin 9(DB9 pin 6).

Right so those wires now go to the ground and 5volt pins of the teensy i assume and if I plug the teensy to the computer, and touch the board with the pen i should see the light come on?
Are there any other pins that need to be grounded?


Title: Re: Converting Wacom XD-0912-R from Serial to USB
Post by: bernard on September 16, 2011, 08:25:44 PM
I assume you picked the good side of the regulator (check pictures in other threads: this is the same regulator in all Wacom boards since the Ultrapads).

GND: you just need to hook the Teensy GND at one spot (for now).    You can check that your ground is okay by testing the vias (holes) on the side of the board where you have a "ground plane" or "ground area" -- this is a big large trace covering all the "holes" -- this is typically ground.  So check that the Teensy GND pin connects with theses vias with your multimeter.

Plug the USB and pray -- if you see something weird, (your computer instantly shutting down, tablet not responding, smoke) -- disconnect right away.  Have your pen ready to try it quickly and have the Wacom tablet led in sight.  Your pen must be touching/tapping the sensor board (the bare PCB is fine) to have the led blink.



Title: Re: Converting Wacom XD-0912-R from Serial to USB
Post by: gordon13 on September 17, 2011, 02:40:15 AM
We have power! Connected it up and the board (led) responds to pen clicks.


Title: Re: Converting Wacom XD-0912-R from Serial to USB
Post by: gordon13 on September 17, 2011, 03:54:04 PM
I think Ill be lucky if it still works.. I now realize that some of the pads were in the middle of tracks which are now broken since they were ripped off. Its very messy and cant see where the tracked were meant to go. But Ill try and fix them, maybe find some points along the tracks and solder single copper wire or something.
I hope its not dead


Title: Re: Converting Wacom XD-0912-R from Serial to USB
Post by: bernard on September 17, 2011, 04:00:46 PM
it is most likely not dead -- I say more than 75% chances that you can make it work.


Title: Re: Converting Wacom XD-0912-R from Serial to USB
Post by: gordon13 on September 17, 2011, 04:03:50 PM
I was wondering if there was a circuit diagram somewhere that shows all the tracks without the markings? some of the tracks are underneath white lines and its hard to see where they go exactly.


Title: Re: Converting Wacom XD-0912-R from Serial to USB
Post by: bernard on September 17, 2011, 04:20:27 PM
You have to use the multimeter to track down traces. 

----

But before doing so, you have to know **which ones** you need to connect.  Is that identified already?  Can you tell me which ones (draw marks on your picture)

----

The multimeter (continuity tester -- the beep) is the best tool for this. Just following "visually" is very difficult and the chance that you get it wrong is high, you do not want to start to uncover the "wrong" trace. 

So find a spot to put your probe.  You have to make sure your probe is connecting by ... finding another spot and connecting the other probe. When you have a firm "lock" on one probe, then try to probe the trace and find the signal elsewhere.  If your probe tip is very sharp, it will go through the PCB protection layer and will connect.  Else, use an exacto knife, a small sand paper or whatever to gently scratch a little portion of the trace so you can probe it.   


Title: Re: Converting Wacom XD-0912-R from Serial to USB
Post by: gordon13 on September 17, 2011, 05:33:04 PM
Yep thats what Ive been doing however because of the tracks being so small and painted over and broken, its hard to tell exactly which ones were meant to be connected. Thats why I was wondering if there was a diagram, so I can see which points are actually meant to be connected

But maybe Im misunderstanding what you mean?



Title: Re: Converting Wacom XD-0912-R from Serial to USB
Post by: gordon13 on September 17, 2011, 09:16:54 PM
Oh man Im so happy right now! Even after those scratched tracks etc, the tablet works!

It turns out the even though some of the tracks are broken, the chip was removed, which means theyre not in use by the board so it just works.
Now I just need to do some more testing to make sure everything is ok.

Bernard, I cant thank you enough for taking the time to help me. The work youve put into Waxbee is very much appreciated. Works straight out of the box, its amazing!


Title: Re: Converting Wacom XD-0912-R from Serial to USB
Post by: bernard on September 18, 2011, 01:08:18 AM
Are you saying you soldered everything and you have a working USB tablet?

If so, please post some pictures of the PCB for others with the same board -- especially that you ripped off traces -- this will occur to other people and the more info we have, the better.


Title: Re: Converting Wacom XD-0912-R from Serial to USB
Post by: gordon13 on September 18, 2011, 02:56:11 AM
Yep I soldered everything, grounded all the points etc and now it works.

Ill summarise what Ive learned from this experience.

From similar threads I knew I needed to ground one of the the point were TR1 was connected. Since the transistor is close to a ground plate I simply soldered some scrap wire between them (make sure to scrape the protective stuff thats on the plate, use a modelling knife and gently scrape it until you can see shiny metal).
Pin/Pad 8 (where the serial chip used to be) needs to be grounded too, so just extend some wire and solder across it to the ground pad (a few millimeters is enough).

The solder pads where the serial chip used to be, were broken so I had to improvise and find another point along the track. To do that I took a high resolution picture and took it in photoshop and painted using the brush tool and shift+click along the track, from the broken point, to see where it leads. In my case the track went to an unused pad which was perfect for soldering the Tx/Rx wire.
If there is no other solder pad along the track you can always scratch off the protective layer and solder directly onto it.

If a important track is broken and the tablet doesn't work, it might be possible to fix it with a conductive ink pen (I think. I haven't tried since it ended up working after all)

When everything is soldered up connect the teensy to usb and fire up the Waxbee software and select the right tablet (in this case XD-0912-R).
When the program process finishes, you should instal the Wacom drivers and the tablet should be detected and the tablet should now work via USB.

Ill post some pictures with annotations later today.


Title: Re: Converting Wacom XD-0912-R from Serial to USB
Post by: gordon13 on September 18, 2011, 05:13:07 PM
Heres a picture of the mod itself:

http://dl.dropbox.com/u/4249784/P1150964.JPG

Hope this helps someone.


Title: Re: Converting Wacom XD-0912-R from Serial to USB
Post by: bernard on September 18, 2011, 05:42:27 PM
Nice work!

BTW, there are other GND and VCC holes on the Teensy (near the microswitch) -- those work equally and are a bit more difficult to solder. I like these because the wires end up "away" from the USB connector.


Title: Re: Converting Wacom XD-0912-R from Serial to USB
Post by: gordon13 on September 18, 2011, 06:26:06 PM
To be honest, I only saw the other two holes after it was too late and was too lazy to resolder them :P But youre right, it would be more practical. I will probably end up moving the wires when I get the enclosure done


Title: Re: Converting Wacom XD-0912-R from Serial to USB
Post by: Alan on December 25, 2012, 09:27:23 PM
I want to mod my serial tablet so I don't need a power-supply, I don't care about usb emulation, will this also work?
a pl2303 rs232 to usb convertor and this small cheap device to power the tablet:
http://www.ebay.com/itm/DC-DC-adjustable-step-up-Power-Module-solar-battery-boost-module-3V-to-5V-9V-1A-/280754693171

thanks

edit:
can't test it yet myself, because I haven't received yet the tablet.


Title: Re: Converting Wacom XD-0912-R from Serial to USB
Post by: Aerendraca on December 26, 2012, 12:05:47 AM
I'm not 100% sure of the power requirement of a serial tablet, I imagine 9V at 500mA (tops) but Bernard can probably advise you better here. So long as the tablet uses less than 9V @ 800mA of current this device should be up to the task. My only point to note is that this appears to be a buck-boost regulator which employs switching technology which can cause radio interference and may affect the function of the tablet (jitters!).

These things are super cheap though so you could always get one and see if there is any interference created by it. If it does cause problems you may be able to work around this by building a faraday cage from an old antistatic bag (untested but might work).


Title: Re: Converting Wacom XD-0912-R from Serial to USB
Post by: bernard on December 26, 2012, 08:19:53 AM
power requirements are under 150mA maybe even less than 100mA in practice.  Have you read the conversion posts? some talk about power.

yes you can power it using USB. It _will_ work with a Teensy but it might be overkill. Else try to find power usb cables. (contains some electronic, not sure how it works).


Title: Re: Converting Wacom XD-0912-R from Serial to USB
Post by: Alan on December 26, 2012, 12:06:12 PM
In another topic you said 60ma@5v when operating


Title: Re: Converting Wacom XD-0912-R from Serial to USB
Post by: Alan on December 26, 2012, 02:14:21 PM
also found this
http://www.techstore4u.com/index.php?route=product/product&product_id=41020#
with pic:
http://www.accessotronik.com/product_p/zip-cell-b9v-b_c101.htm#

what kind of dc connector does the ac/dc adapter have (barrel size)?
http://www.ebay.com/sch/i.html?_odkw=usb+barrel&_osacat=0&_from=R40&_trksid=p2045573.m570.l1313&_nkw=usb+barrel&_sacat=0


Title: Re: Converting Wacom XD-0912-R from Serial to USB
Post by: bernard on December 27, 2012, 05:27:01 AM
i will try to check it out when i am back home after the holidays.  this cable probably outputs 5volts. this is not what the tablet wants through the barrel input. 5volts is the internal operating voltage. you need to open the tablet and solder 2 wires to feed the USB 5volt.


Title: Re: Converting Wacom XD-0912-R from Serial to USB
Post by: Alan on December 27, 2012, 12:39:03 PM
Why is 9-12 adapter necessary? For the rsr232 TTL signals?

the cable outputs what the little usb device (in the link) outputs, which is 9v.

Is it possible to use usb 5v by modding the tablet while keeping the serial interface alive for use with a rs232 to usb converter?


Title: Re: Converting Wacom XD-0912-R from Serial to USB
Post by: Alan on December 30, 2012, 02:46:57 AM
Finally got my tablets, 3 intuos2 serial with 2 pens, for 22 euro's :)
I didnt realize there are no compatible drivers for windows 7 64bits, there are workarounds, but none worked for me (installing drivers 610-6 in win2000 compatibility, then vista) tried it many times, and on 2 computers, with the same prolific adaptor.
an "other devices" is found called "wacom xd", xd-0608-r in properties, no drivers are installed.

any ideas?



Title: Re: Converting Wacom XD-0912-R from Serial to USB
Post by: Alan on December 30, 2012, 04:34:50 PM
I'm looking for a cheap-ass alternative to teensy, because I need more than one and they are quite expensive here

will this work, hardware wise?
http://dx.com/p/nano-v3-0-avr-atmega328-p-20au-module-board-usb-cable-for-arduino-118037?rt=1&p=2&m=2&r=3&k=1&t=1&s=148046&u=118037



Title: Re: Converting Wacom XD-0912-R from Serial to USB
Post by: Alan on December 30, 2012, 11:21:36 PM
http://www.ebay.com/itm/Iduino-NANO328-V3-5V-16Mhz-100-compatible-with-Arduino-s-IDE-/261119461707
el-cheapo alternative and widely available


Title: Re: Converting Wacom XD-0912-R from Serial to USB
Post by: bernard on December 31, 2012, 06:11:59 AM
Unless you want to play with the code and adapt it, you must use an ATMEGA32U4-based breakout board.  There are a few of these.

I am curious, how much the Teensy 2.0  turns out to be for you (shipping included)?






Title: Re: Converting Wacom XD-0912-R from Serial to USB
Post by: Alan on December 31, 2012, 07:14:51 AM
Yes, I like too mess around with code and make it cheaper for everyone
$29 including shipping


Title: Re: Converting Wacom XD-0912-R from Serial to USB
Post by: Alan on December 31, 2012, 07:17:16 AM
Why an ATMEGA32U4? For your code to be compatible?


Title: Re: Converting Wacom XD-0912-R from Serial to USB
Post by: bernard on December 31, 2012, 08:21:03 AM
yeah to directly use it without modifications.  Else, you can use any decent usb-enabled CPU. Of course if you stick with AVR more of the code will be re-usable.

Not all AVR cpus are created equals in terms of USB capabilities. Internal buffer sizes, number of endpoints etc. For typical HID stuff and Wacom it should not be too much of a problem I think. Would have to check the specs for the USB device.