iPod breakout board

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iPod breakout board

Postby Chlazza » Thu Aug 05, 2010 12:15 am

Hey guys,
Long time Sparkfun user/first time forum member here. :)
I just wanted to show this off a bit, nothing fancy but I'm pretty happy with how it turned out.
I built an iPod connector breakout board using Sparkfun's "iPod Connector Male Style 1" (DEV-00633). It was meant to be a simple exercise in layout (I remember thinking "It's a breakout board; how hard can it be?" - Hah!) but I wound up running about three iterations through BatchPCB before getting a 'final' version. Definitely a learning experience, but I now have something I built that I use on a regular basis. Take a look:
ImageImage
ImageImageImage
Detailed build log and related files here: http://www.chlazza.net/ultradock.html

Edit: Fixed link.
Last edited by Chlazza on Sun Aug 08, 2010 2:30 pm, edited 1 time in total.
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Re: iPod breakout board

Postby Selenaut » Fri Aug 06, 2010 8:42 am

I recognize the two audio jacks and the charger, but what do the other ones do?
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Re: iPod breakout board

Postby Chlazza » Fri Aug 06, 2010 12:42 pm

The yellow one is a Composite Video Out and the black cube next to it it S-Video Out. As far as I know video out is only supported on a handful of iPods.
The silver connector next to the USB-B socket is a Firewire (1394A) jack. No recent iPod uses this port, it's there mostly so I can charge and sync my old iPod Photo.
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Re: iPod breakout board

Postby Selenaut » Fri Aug 06, 2010 6:25 pm

Ah. Do you hook it up to watch movies on your TV?
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Re: iPod breakout board

Postby Chlazza » Sat Aug 07, 2010 2:39 pm

Nah, I use it pretty much only for music, but I figured that I couldn't call it a complete breakout board unless I had all the pins wired to the appropriate sockets.
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Re: iPod breakout board

Postby Conrthomas » Tue Aug 10, 2010 11:50 am

Very Cool. Do you plan to release the PCB files or to sell them? I'd definitely be interested.
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Re: iPod breakout board

Postby Chlazza » Thu Aug 12, 2010 1:17 pm

Both, actually!
I have a page up (here) with all the Gerber files and related.
If you want to buy a production quality board (gold plated instead of tin plating, correct thickness for the iPod connector) you can buy one here.
I'm working on putting together kits as well, thats taking a bit longer than I intended however.
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Re: iPod breakout board

Postby Conrthomas » Fri Aug 13, 2010 9:35 am

Oh, schweet! Thanks! I will definitely be buying one from you soon. I can't (in good conscience) leech off your work, I'd rather support your ideas.
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Re: iPod breakout board

Postby Conrthomas » Fri Aug 13, 2010 10:11 am

So I can use this:
http://www.sparkfun.com/commerce/produc ... cts_id=633
with your board, correct?
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Re: iPod breakout board

Postby Chlazza » Fri Aug 13, 2010 12:02 pm

Correct!
That is the exact part I used with the initial prototype board. I later switched to connectors from a different supplier, but they appeared to be identical to the Sparkfun part you linked.
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Re: iPod breakout board

Postby st2000 » Sun Aug 15, 2010 7:21 am

For your next design revision...

====1====

As you might have figured out (or at least I assume) after upgrading you iPod(s) you no longer get any video out of your break-out board (or do you???).

What I am thinking you might be able to do is buy an Apple video cable, extract the chip and install it into your break-out board. Or, at the very least, integrate an Apple video cable into your design. I am assuming Apple uses the serial I/O of an iPod 30 pin interface to communicate with a chip in the cable. There's not much you can do to beat the system if it's what I think it is. That is, unless Apple implemented it badly (i.e. used the same starting challenge sequence after, say, a iPod reset).

Note: This is not a way around Apple's measures to control after market products! You still need to buy a real Apple video cable.

Note: I am making a number of guesses. You will have to figure out the details. My guesses are based on chips available from TI.com:
http://www.ti-estore.com/Merchant2/merc ... bq26100EVM

====2====

Old iPods charged from the 12V fire wire line. New iPods charge from the 5V USB wire line. Why not add a buck-converter when attaching, say, an iPhone to a computer's fire wire line and a boost-converter when attaching a really old iPod to a computer's USB port. There are plenty of single chip solutions that only need a half dozen external components. You could lay them out on you PCB and leave it up to the end user if he/she wants to populate them.

-good luck
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Re: iPod breakout board

Postby st2000 » Sun Aug 15, 2010 3:10 pm

Chlazza wrote:... correct thickness for the iPod connector)...


Are the board made here at sparkfun's PCB batch service too thick for the iPod connectors sold here at sparkfun?

-thanks
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Re: iPod breakout board

Postby Chlazza » Mon Aug 16, 2010 12:06 pm

st2000 wrote:As you might have figured out (or at least I assume) after upgrading you iPod(s) you no longer get any video out of your break-out board (or do you???).

What I am thinking you might be able to do is buy an Apple video cable, extract the chip and install it into your break-out board. Or, at the very least, integrate an Apple video cable into your design. I am assuming Apple uses the serial I/O of an iPod 30 pin interface to communicate with a chip in the cable. There's not much you can do to beat the system if it's what I think it is. That is, unless Apple implemented it badly (i.e. used the same starting challenge sequence after, say, a iPod reset).

Actually I hadn't explicitly tested video out with anything other than my (4th gen Classic?) iPod Photo.
I just tested my iPhone with composite video and your right, it doesn't do anything. Thanks for the heads up. :)
To be honest, I'm not thrilled about the idea of cannibalizing Apple video cables if I can help it. Even cheap South-Asia versions of the adapter are at least $10 each, and thats an extra ten bucks I'd need to add to the price of anything I produce. Reverse engineering an official video cable may be in my future, although if its anything more complex than a resistor value on the accessory select line or a static challenge/response on the serial line I'll probably be wandering into DMCA territory.

st2000 wrote:Old iPods charged from the 12V fire wire line. New iPods charge from the 5V USB wire line. Why not add a buck-converter when attaching, say, an iPhone to a computer's fire wire line and a boost-converter when attaching a really old iPod to a computer's USB port. There are plenty of single chip solutions that only need a half dozen external components. You could lay them out on you PCB and leave it up to the end user if he/she wants to populate them.

As a matter of fact I had looked into various charging solutions when doing the initial design, but the hassle of layout, limited board space, and fear of destroying an iPod (or attached computer) with bad circuit design is why there isn't an external power jack or similar on the board already. I figured I'd break out the connector pins and let the user use a MintyBoost or similar if they needed more power.

Here is my logic:
When going from USB->Firewire I'd be worried about current supply. To stay within the bounds of the USB spec I would need to limit current draw to 100mA (or 500Ma if the board 'asked for permission' over USB, but that is a bit complex). Correct me if I'm wrong but the ratio between the voltage and current would be maintained and thus if the board converted the USB power to 12V the current would drop significantly. Would a Firewire iPod charge at less than 100mA? Would it charge in a reasonable amount of time?
Regarding Firewire->USB charging: since Firewire was intended to operate full size hard drive I assume it provides more than 100mA, so in theory I could just throw a linear regulator and a couple resistors on the board and call it good. Problem is I'd still need to add some extra logic to detect if the device doesn't use Firewire (not sure how to do this), cut off Firewire data lines (I have reason to believe they've been repurposed in newer devices and driving signals on them could result in undefined behavior in the device), pull the USB signal lines to appropriate levels (so it will actually see the board as a charger), and to disconnect the charge circuitry when something is plugged in the USB socket. If I screw that logic up I could potentially damage somebodies computer or expensive Apple device, and I really don't want to do that. As I said above, I just broke out the pins and decided to let the user pick their power supply.
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Re: iPod breakout board

Postby Chlazza » Mon Aug 16, 2010 12:15 pm

st2000 wrote:
Chlazza wrote:... correct thickness for the iPod connector)...


Are the board made here at sparkfun's PCB batch service too thick for the iPod connectors sold here at sparkfun?

-thanks


Correct, if you are using them as board edge straddling connectors.
By my measurements BatchPCB boards have a thickness of about 1.6mm while the ideal width appears to be 1.3mm.
It is possible to force the connector onto the edge of the board, but you'll end up with something that looks like this:
Image
See how the pins are alternating high/low? They should all be (mostly) even.
During testing I destroyed an iPod nano this way - I had a connector on a BatchPCB board and as far as I can tell some of the pins only made partial contact. I got the iPod to light up and enumerate on the USB bus, left it to charge, came back a while later and discovered it with a blank screen, back light on, making an ominous buzzing noise. It hasn't worked since but it does get very warm when I plug it in. :D
Last edited by Chlazza on Mon Aug 16, 2010 4:51 pm, edited 2 times in total.
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Re: iPod breakout board

Postby st2000 » Mon Aug 16, 2010 3:41 pm

Ok, ok, I see what you mean (wrt charging iPods). But I think if you look at the 30 pin iPod definition you will see different power inputs for the firewire and USB. So at least that side is easy. Now it's just getting the power converted.

Also, do your self a favor and review what the resistor matrix you need to fake a USB recharging iPod into thinking you have enough power w/o having to talk to it. Adafruit has a nice write up on the subject.

As far as the cable is concerned. I'm betting there is a chip hanging off the serial port. You could test this by only attaching those wires to a iPod and seeing if video can then be played. If I'm right, you could simply add a second reverse gender 30 pin iPod connector and route the serial port pins through. Then, simply plug in an Apple authenticating cable.

Regardless, this is the type of breakout board I would be looking for. On that routes the connections through allowing me to do what I want between the iPod and the iPod appliance (i.e. maybe I'll add a 5 volt source so as to be able to use my iPod Touch on an old iPod only appliances. And believe me I have plenty of them!).
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