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HOWTO: White PDN Serial Interface


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#1 RobBrownNZ

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Posted 08 March 2011 - 06:32 AM

OK, so the instructions are done. All feedback welcome!

http://www.cobblewar...wpdnserial.html


White PDN Serial Interface

RobBrownNZ's Original Instructions and images at Cobbleware.com
Reposted here with permission. THANKS, Rob! :good:


NOTE: I'm offering this guide in the hope that it will be useful. While you are welcome to use this description as a guide to connecting a serial interface to your PDN, I will not accept any responsibility for the consequences. It's all at your own risk.

With that out of the way, this page is about connecting a serial interface to the CON4 connector inside a White Pandigital Novel. This has been discussed on SlateDroid, head over there to see the details. In particular, I won't explain how to disassemble your PDN as there are guides on SlateDroid. I'll just give the standard warning: there are lots of parts that are held together with double-sided tape, don't bend the plastic too hard or you'll break it!

The schematic for the adapter is shown below. R1 needs to be there, its value should be around 3k - 5k. I used 4k7. R2 is optional, if you don't put it in then you may find that the PDN powers up when you connect USB to the adapter. That's not a great thing so I'd generally recommend that you put R2 in. Value should be 1k - 5k, I used 1k5.

You'll notice that pins 1, 2, and 4 on the PDN are all "+3V3". They're connected together in the PDN, and so you can connect to whichever of them is convenient for you- there's no difference at all. The same goes for "GND" on pins 3, 8, 14, and 18.


Posted Image


First, you need to gather the parts:

  • Flat flex adapter board - Digikey
  • 20-way flat flex (I used the 3" one) - Digikey
  • USB-to-Serial adapter I like this one from - SparkFun
  • Resistors - I used a 4k7 (R1) and a 1k5 (R2), but as I said, it's not critical. A couple of 3k3s would be fine. Any half-decent electronics store should have them: Radio Shack (USA), Dick Smith (Australia/NZ) etc.
  • Hookup wire, soldering iron and solder, etc.
By the way, I'm using leaded resistors for this description because they're more readily available than SMD ones. If you can get SMD (0805 size preferably) then use them: the adapter board is designed for them and the finished board will be more robust.


Posted Image



Now prepare the resistors by bending one lead over 180 degrees so that the two leads are parallel, and then bend both leads 90 degrees a couple of millimetres below the body of the resistor. If you have needle-nosed pliers, clamp the leads between the body of the resistor and the bend, as this will prevent the resistor from being stressed while you bend the leads.



Posted Image



Next, trim the resistor legs so that they have just a short protrusion after the 90 degree bend - a couple of millimetres or so.



Posted Image




Solder the resistors to the PCB. When looking at the board as shown in the picture below, R1 is on the left.

I've indicated the pin numbering on the adapter board, in red.




Posted Image




Add 3 short wires:

  • From pin 4 to the end of R1 that's further from the centre of the PCB. Remember you could use pin 1 or 2 instead of 4.
  • From pin 10 to the end of R2 that's closer to the centre of the PCB.
  • From pin 9 - it will go to the end of R1 that's closer to the centre of the PCB, but don't attach the other end yet.
Note that this picture is taken from the opposite angle to the previous picture, so now R1 is on the right.



Posted Image



Add the wires that will connect to the USB-Serial adapter. The PDN's Tx wire (yellow in the picture below) has to go through the same hole as the wire from pin 9 that you didn't connect before. You might find it easier to twist the ends of the two wires together before putting them through the hole in the PCB. They connect to the end of R1 that's closer to the centre of the PCB.

The PDN's Rx wire (brown in the picture) connects to the end of R2 that's further from the centre of the PCB. The GND wire (black in the picture) goes to pin 3, 8, 14, or 18 - in the picture I've connected it to pin 8.



Posted Image



Now connect the wires to the USB-serial adapter. Tx and Rx are swapped, so the yellow wire (PDN Tx) goes to the USB-serial adapter's Rx input. The brown wire (PDN Rx) goes to the USB-serial adapter's Tx output.



Posted Image



Finally, connect it all together. The flat flex needs to have its contacts down when viewed from the angle in the picture below.



Posted Image



Connect the USB-serial adapter to your PC and configure a serial terminal program for 115200 bits per second, no parity, 8 data bits, 1 stop bit, and no flow control. For a terminal program, I prefer TeraTerm.

When you power up the PDN, you'll see messages from U-Boot, the Linux boot process, and Android starting up. If you bang on your keyboard immediately after powering up (or resetting) the PDN, you can interrupt U-Boot and type commands to it (start with "help").

I'd be interested in any feedback anyone may have on these instructions. Hop on over to the SlateDroid forum and join the discussion!

Edited by mrsburnout, 01 August 2012 - 09:39 AM.
added text/images

  • Mp4, mrsburnout, rebthor and 1 other like this

#2 mrsburnout

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Posted 23 July 2012 - 11:46 AM

OK, so the instructions are done. All feedback welcome!

http://www.cobblewar...wpdnserial.html


Rob's original post above^^ has been split from CON4 - The Quest to Trace It. JTAG? Something else?.

:clapping: Thank you, Rob!!

Edit: Added in the Wiki here: Hardware Modifications - Solved (wiki link subject to change whenever the IPBoard "breaks" ;))

Edit: Updated first post with text/images - thanks for permission to post, RobBrownNZ. :)

Edited by mrsburnout, 01 August 2012 - 09:40 AM.

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#3 Trek24ever

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Posted 13 June 2013 - 08:36 PM

Nice job - I'll give it a try! :drinks:

#4 GeoLeo

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Posted 02 January 2014 - 04:07 PM

Rob,

I just acquired a white Pandigital and need to get my post in. I'm just curious, what would I use the serial interface for. I'm a tech kind of person and have used serial interfaces in the old days when that was all you had to work with. I'm talking RS232 25 pin connectors and such.

#5 mrsburnout

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Posted 06 January 2014 - 11:57 AM

Rob's original post above^^ has been split from CON4 - The Quest to Trace It. JTAG? Something else?. :clapping: Thank you, Rob!! ...snip



Rob,I just acquired a white Pandigital and need to get my post in. I'm just curious, what would I use the serial interface for. I'm a tech kind of person and have used serial interfaces in the old days when that was all you had to work with. I'm talking RS232 25 pin connectors and such.


Hello GeoLeo,

I would like to point out the bold text quoted from my post above, and recommend clicking the link to read the original topic.

Good luck with your pdn, happy reading..
and welcome to sld ~


gnarlyc's reply in that very thread: http://www.slatedroi...post__p__147682

Now THAT cleared up some confusion. Thank you again.

And... I have my PDN back! It worked! This is wonderful. Now, I can break it over and over again! ;)


YMMV = Your Mileage May Vary - Not even OEM FW is guaranteed "safe" to flash.

Hey! Newbies (n00bs) - Click the blue links ;) - Forum Rules

"Dream as if you'll live forever. Live as if you'll die today." ~James Dean
"Slatedroid: Where all the advice is free, even advice you don't want." ~Mark Adams #113449
"Women are Angels. When someone breaks our wings - we simply continue to fly - on a broomstick. We are flexible like that."

Posted Image ~cheers

#6 lenyoez1

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Posted 02 September 2014 - 01:21 AM

OK, so the instructions are done. All feedback welcome!

http://www.cobblewar...wpdnserial.html


White PDN Serial Interface

RobBrownNZ's Original Instructions and images at Cobbleware.com
Reposted here with permission. THANKS, Rob! :good:


NOTE: I'm offering this guide in the hope that it will be useful. While you are welcome to use this description as a guide to connecting a serial interface to your PDN, I will not accept any responsibility for the consequences. It's all at your own risk.

With that out of the way, this page is about connecting a serial interface to the CON4 connector inside a White Pandigital Novel. This has been discussed on SlateDroid, head over there to see the details. In particular, I won't explain how to disassemble your PDN as there are guides on SlateDroid. I'll just give the standard warning: there are lots of parts that are held together with double-sided tape, don't bend the plastic too hard or you'll break it!

The schematic for the adapter is shown below. R1 needs to be there, its value should be around 3k - 5k. I used 4k7. R2 is optional, if you don't put it in then you may find that the PDN powers up when you connect USB to the adapter. That's not a great thing so I'd generally recommend that you put R2 in. Value should be 1k - 5k, I used 1k5.

You'll notice that pins 1, 2, and 4 on the PDN are all "+3V3". They're connected together in the PDN, and so you can connect to whichever of them is convenient for you- there's no difference at all. The same goes for "GND" on pins 3, 8, 14, and 18.


WyHWL.jpg


First, you need to gather the parts:
 

  • Flat flex adapter board - Digikey
  • 20-way flat flex (I used the 3" one) - Digikey
  • USB-to-Serial adapter I like this one from - SparkFun
  • Resistors - I used a 4k7 (R1) and a 1k5 (R2), but as I said, it's not critical. A couple of 3k3s would be fine. Any half-decent electronics store should have them: Radio Shack (USA), Dick Smith (Australia/NZ) etc.
  • Hookup wire, soldering iron and solder, etc.
By the way, I'm using leaded resistors for this description because they're more readily available than SMD ones. If you can get SMD (0805 size preferably) then use them: the adapter board is designed for them and the finished board will be more robust.


T43zp.jpg



Now prepare the resistors by bending one lead over 180 degrees so that the two leads are parallel, and then bend both leads 90 degrees a couple of millimetres below the body of the resistor. If you have needle-nosed pliers, clamp the leads between the body of the resistor and the bend, as this will prevent the resistor from being stressed while you bend the leads.



lWvsd.jpg



Next, trim the resistor legs so that they have just a short protrusion after the 90 degree bend - a couple of millimetres or so.



640Zi.jpg




Solder the resistors to the PCB. When looking at the board as shown in the picture below, R1 is on the left.

I've indicated the pin numbering on the adapter board, in red.




h0a5Y.jpg




Add 3 short wires:

  • From pin 4 to the end of R1 that's further from the centre of the PCB. Remember you could use pin 1 or 2 instead of 4.
  • From pin 10 to the end of R2 that's closer to the centre of the PCB.
  • From pin 9 - it will go to the end of R1 that's closer to the centre of the PCB, but don't attach the other end yet.
Note that this picture is taken from the opposite angle to the previous picture, so now R1 is on the right.



bQlWT.jpg



Add the wires that will connect to the USB-Serial adapter. The PDN's Tx wire (yellow in the picture below) has to go through the same hole as the wire from pin 9 that you didn't connect before. You might find it easier to twist the ends of the two wires together before putting them through the hole in the PCB. They connect to the end of R1 that's closer to the centre of the PCB.

The PDN's Rx wire (brown in the picture) connects to the end of R2 that's further from the centre of the PCB. The GND wire (black in the picture) goes to pin 3, 8, 14, or 18 - in the picture I've connected it to pin 8.



OkXD5.jpg



Now connect the wires to the USB-serial adapter. Tx and Rx are swapped, so the yellow wire (PDN Tx) goes to the USB-serial adapter's Rx input. The brown wire (PDN Rx) goes to the USB-serial adapter's Tx output.



rMoRU.jpg



Finally, connect it all together. The flat flex needs to have its contacts down when viewed from the angle in the picture below.



HAqDF.jpg



Connect the USB-serial adapter to your PC and configure a serial terminal program for 115200 bits per second, no parity, 8 data bits, 1 stop bit, and no flow control. For a terminal program, I prefer TeraTerm.

When you power up the PDN, you'll see messages from U-Boot, the Linux boot process, and Android starting up. If you bang on your keyboard immediately after powering up (or resetting) the PDN, you can interrupt U-Boot and type commands to it (start with "help").

I'd be interested in any feedback anyone may have on these instructions. Hop on over to the SlateDroid forum and join the discussion!

 

Thanks man!