Kindle 3 serial plug designs

blkhawk · 09-18-2010, 11:33 PM

Hi,

I thought i might as well post the mechanical design I use for my Kindle serial plug since the other plug designs i have seen here do not contain the notch you need to insure a good connection with the 2 serial pins.

You can see why you need the notch when you take apart the socket the K3 has. I wish i had done that at the start because i had lots of headscrating moments why the damn plug would work one moment and not the next.

It also led me to discard a perfectly good sparkfun level converter as "broken".

Right now i use a Bus Pirate to interface the kindle.

To etch you need the following:

Etching solution (natriumpersulafte)
a single sided copper clad board (a really small piece of that board really)

a laserprinter
a page of *inkjet* glossy photo paper
an old toothbrush

print the .brd file with EAGLE in Black+White to the paper and iron it to the copper side of the board. The printout should look like the png I included.

use some warm running water and the toothbrush to remove the paper.

etch the board in the etching solution and then cut the board down like the one in the attached photo. Your board will also be probably too thick. you need to file it down by 1/3 if you have standard thickness board.

after that attach a suitable 1.8v serial adapter or level converter and enjoy.

-blkhawk

[ad] come to #kindle @ irc.freenode.net [/ad]

dinkus · 09-20-2010, 09:32 PM

thanks blkhawk. Your method of etching sounds much easier than ones I've found online requiring UV lights and transparencies - that is, unless thats what you mean by "etch the board.."

To use the bus pirate for the serial port, how do you configure it? Based on reading I've done, seems like you need to use the open collector and UART mode and feed the bp a constant 1.8v source? Do you have an easy suggestion for the 1.8v beyond a bench supply?

As should be clear I have very little electronics experience. I see there's now a much easier way to hack the kindle 3 but this looks like a good way to learn and have some fun.

Tiersten · 09-20-2010, 09:41 PM

The laser printer toner method is good for small runs of reasonably simple PCBs but if you want to do more then you'd want to use photoresist and a mask with UV exposure.

The Kindle supplies 1.8V on one of the plug connectors. Picture here.

blkhawk · 09-21-2010, 01:58 AM

Quote:

Originally Posted by dinkus

thanks blkhawk. Your method of etching sounds much easier than ones I've found online requiring UV lights and transparencies - that is, unless thats what you mean by "etch the board.."

no, I meant by etching put it in hot etching solution and stir it.

Quote:

Originally Posted by dinkus

To use the bus pirate for the serial port, how do you configure it? Based on reading I've done, seems like you need to use the open collector and UART mode and feed the bp a constant 1.8v source? Do you have an easy suggestion for the 1.8v beyond a bench supply?

yes, start UART mode with "m3" then choose baudrate "9". the Rest of the settings are default. Enable pullup Resistors with "P" then Start the transparent UART Bridge mode with "(3)".
You can get the constant 1.8v directly from the kindle. the shortest pin on my mask has 1.xv on it.

yifanlu · 05-29-2011, 06:44 PM

Sorry for bumping an old thread, but if anyone can make a plug for me (even better if an entire cable), I can pay them. I would love to have one for experimenting with the Kindle 3, but I don't have any of the materials to make one.

seaniko7 · 06-15-2011, 10:24 AM

This one flies to you, yifanlu.

yifanlu · 06-15-2011, 12:05 PM

Quote:

Originally Posted by seaniko7

This one flies to you, yifanlu.

Thank you so much! Now I can do some of the kernel hacking that I wanted to do, but was afraid of bricking.

mark03 · 06-15-2011, 03:20 PM

At the risk of hijacking the thread, does anyone know if there are other serial interfaces available inside the Kindle 3?

The i.MX35 has three UARTs, and it's easy to find which balls the signals are on from the Freescale's tech docs, but I have no way of knowing if those balls are routed anywhere. Amazon's kernel is finding all three and assigning them ttymxc0, ttymxc1, and ttymxc2. Of course, the console getty process runs on ttymxc0.

I've thought of hooking up a GPS with serial output, but it seems pretty dangerous to disable the serial console for that purpose. It's the last line of defense if I do something stupid and need u-boot access. Looking at all those test points on the PCB, I wonder if some of them are ttymxc1 or ttymxc2? Anyone know?

yifanlu · 06-15-2011, 03:29 PM

Quote:

Originally Posted by mark03

At the risk of hijacking the thread, does anyone know if there are other serial interfaces available inside the Kindle 3?

The i.MX35 has three UARTs, and it's easy to find which balls the signals are on from the Freescale's tech docs, but I have no way of knowing if those balls are routed anywhere. Amazon's kernel is finding all three and assigning them ttymxc0, ttymxc1, and ttymxc2. Of course, the console getty process runs on ttymxc0.

I've thought of hooking up a GPS with serial output, but it seems pretty dangerous to disable the serial console for that purpose. It's the last line of defense if I do something stupid and need u-boot access. Looking at all those test points on the PCB, I wonder if some of them are ttymxc1 or ttymxc2? Anyone know?

Even if you disable the serial console in the kernel, it still works on the uBoot bootloader which allows you to upload a new kernel.

seaniko7 · 06-15-2011, 04:11 PM

How about using usb serial interface, mark03 ?

mark03 · 06-15-2011, 05:47 PM

@yifanlu, hey, good point! So I could disable the console in inittab and not really lose anything (I use ssh over usbnet)? Hopefully the u-boot output wouldn't confuse the freshly-started GPS module during boot.

@seaniko7, do you mean internally or externally? I am hoping to fit this inside the Kindle in the space normally occupied by the 3G card (I have the wifi-only model). I could potentially get USB from the mini-pcie connector pads, but usb-serial inside the case would add space and complexity.

I'm still curious about all those TPs. Wish someone would leak a schematic

I'm looking for a good place to piggyback I2C also. (Leading contender thus far is the WM8960 codec.)

seaniko7 · 06-15-2011, 06:18 PM

@mark03, actually im talking about usb serial mode. You can access it just like usbnetwork. (/usr/sbin/usbserial)

Matan · 06-15-2011, 06:30 PM

Quote:

Originally Posted by seaniko7

@mark03, actually im talking about usb serial mode. You can access it just like usbnetwork. (/usr/sbin/usbserial)

But in this mode the Kindle is a USB device, so it needs to connect to a USB host. It can't be used for connecting to peripherals such as a GPS module.

seaniko7 · 06-15-2011, 06:52 PM

@Matan, uh you're right, but he can still use it to check bootup process after uBoot start.

mark03 · 06-15-2011, 07:24 PM

Great. It's good to have options.

Still, it would be even better if the other two UARTs' txd/rxd were accessible on the board. We need some awesome Russians with needles!

09-20-2010, 09:41 PM	#3
Tiersten Guru Posts: 987 Karma: 8641 Join Date: Sep 2010 Device: Kindle 3G+WiFi	The laser printer toner method is good for small runs of reasonably simple PCBs but if you want to do more then you'd want to use photoresist and a mask with UV exposure. The Kindle supplies 1.8V on one of the plug connectors. Picture here. Last edited by Tiersten; 09-20-2010 at 09:43 PM.

06-15-2011, 10:24 AM	#6
seaniko7 wannabe developer Posts: 192 Karma: 156548 Join Date: Mar 2011 Device: Kindle: 2xKeyboard, Classic, 2xTouch, 2xPW, PW2; Onyx: Boox M92	This one flies to you, yifanlu. Attached Thumbnails

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09-20-2010, 09:32 PM	#2
dinkus Junior Member Posts: 5 Karma: 10 Join Date: Sep 2010 Device: kindle 3	thanks blkhawk. Your method of etching sounds much easier than ones I've found online requiring UV lights and transparencies - that is, unless thats what you mean by "etch the board.." To use the bus pirate for the serial port, how do you configure it? Based on reading I've done, seems like you need to use the open collector and UART mode and feed the bp a constant 1.8v source? Do you have an easy suggestion for the 1.8v beyond a bench supply? As should be clear I have very little electronics experience. I see there's now a much easier way to hack the kindle 3 but this looks like a good way to learn and have some fun.

05-29-2011, 06:44 PM	#5
yifanlu Kindle Dissector Posts: 662 Karma: 475607 Join Date: Jul 2010 Device: Amazon Kindle 3	Sorry for bumping an old thread, but if anyone can make a plug for me (even better if an entire cable), I can pay them. I would love to have one for experimenting with the Kindle 3, but I don't have any of the materials to make one.

06-15-2011, 03:20 PM	#8
mark03 Enthusiast Posts: 30 Karma: 10 Join Date: Jun 2011 Device: Kindle 3 wifi	At the risk of hijacking the thread, does anyone know if there are other serial interfaces available inside the Kindle 3? The i.MX35 has three UARTs, and it's easy to find which balls the signals are on from the Freescale's tech docs, but I have no way of knowing if those balls are routed anywhere. Amazon's kernel is finding all three and assigning them ttymxc0, ttymxc1, and ttymxc2. Of course, the console getty process runs on ttymxc0. I've thought of hooking up a GPS with serial output, but it seems pretty dangerous to disable the serial console for that purpose. It's the last line of defense if I do something stupid and need u-boot access. Looking at all those test points on the PCB, I wonder if some of them are ttymxc1 or ttymxc2? Anyone know?

06-15-2011, 04:11 PM	#10
seaniko7 wannabe developer Posts: 192 Karma: 156548 Join Date: Mar 2011 Device: Kindle: 2xKeyboard, Classic, 2xTouch, 2xPW, PW2; Onyx: Boox M92	How about using usb serial interface, mark03 ?

06-15-2011, 05:47 PM	#11
mark03 Enthusiast Posts: 30 Karma: 10 Join Date: Jun 2011 Device: Kindle 3 wifi	@yifanlu, hey, good point! So I could disable the console in inittab and not really lose anything (I use ssh over usbnet)? Hopefully the u-boot output wouldn't confuse the freshly-started GPS module during boot. @seaniko7, do you mean internally or externally? I am hoping to fit this inside the Kindle in the space normally occupied by the 3G card (I have the wifi-only model). I could potentially get USB from the mini-pcie connector pads, but usb-serial inside the case would add space and complexity. I'm still curious about all those TPs. Wish someone would leak a schematic I'm looking for a good place to piggyback I2C also. (Leading contender thus far is the WM8960 codec.)

06-15-2011, 06:18 PM	#12
seaniko7 wannabe developer Posts: 192 Karma: 156548 Join Date: Mar 2011 Device: Kindle: 2xKeyboard, Classic, 2xTouch, 2xPW, PW2; Onyx: Boox M92	@mark03, actually im talking about usb serial mode. You can access it just like usbnetwork. (/usr/sbin/usbserial)

06-15-2011, 06:52 PM	#14
seaniko7 wannabe developer Posts: 192 Karma: 156548 Join Date: Mar 2011 Device: Kindle: 2xKeyboard, Classic, 2xTouch, 2xPW, PW2; Onyx: Boox M92	@Matan, uh you're right, but he can still use it to check bootup process after uBoot start.

06-15-2011, 07:24 PM	#15
mark03 Enthusiast Posts: 30 Karma: 10 Join Date: Jun 2011 Device: Kindle 3 wifi	Great. It's good to have options. Still, it would be even better if the other two UARTs' txd/rxd were accessible on the board. We need some awesome Russians with needles!

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