Comments on: Boom: Pins

By: Dominic

Dominic — Wed, 13 Mar 2013 02:17:00 +0000

Quite a lot of information there. Thanks for the effort.

By: red

red — Sat, 02 Mar 2013 14:05:49 +0000

@ Rainer @41
Strictly speaking all signals are analog.

The encoded information can be digital or analog but all signals are analog in nature on our macro level.
In case of these differential signals they encode bits just as much as a non-differential signal. The only difference is that in the normal case the signal balances around a fixed potential and in the differential case the signal balances against it’s antipotential.
It is just a trick for reducing outside interference.

By: Rainer Brockerhoff

Rainer Brockerhoff — Wed, 02 Jan 2013 12:23:45 +0000

@rva, no further details have been published about the protocol or the chips. I wouldn’t count “charging” as a protocol, though.

By: Rva

Rva — Tue, 01 Jan 2013 12:46:18 +0000

Hi, nice article. I found this cable idea very attractive. I like to have things universal. I am busy with mcu’s and try to use any connection this way to avoid fat cables and clutter and save pins on the chips and cables. The only thing here is what if I want to use two/three protocols at the same time? Charging, using usb data transfer and watching something over hdmi? Will it savely switch fast enough?

A question, what about a serial protocol, like on the old iDevices? It is in there? Do I need a different lightning chipset? Do you know anything about that?
Thank you.

By: Rainer Brockerhoff

Rainer Brockerhoff — Thu, 18 Oct 2012 23:40:44 +0000

@Howard, re #1: suppose you allowed a “dumb” charging cable. It would have the 5 VDC permanently exposed on the open plug (and on both sides!) so if it brushes against some sort of metal object you’d have a nice short circuit. That’s why the plug has power-switching circuitry.
re #3: right, all pictures show contacts on one side only. Putting contacts on both sides in a future device would introduce incompatibilities and make the connector side too thick – the iPod nano teardown I linked to shows that this is already one of the factors limiting device thinness.

By: Howard M

Howard M — Wed, 17 Oct 2012 16:32:48 +0000

Thanks for a comprehensive analysis. Nice to get some clarity

A few things though:

1) You’re right, ‘authentication chip’ is a misnomer – there’s no way to provide all the connectivity required from 8 connections without needing some intelligence on the outside too. I’m still, however, struggling to understand why there couldn’t be some simple dumb-cable fallback option provided – as other commenters here have suggested.

Even just plain ‘ole USB2 – only 4 conductors required; surely the controller in the phone (which will have sensibly disconnected all the internal connections when it sensed a plug being inserted) could detect a ‘dumb’ cable, check if there was 5v present on a certain pin, and if so it could pass the appropriate signals to the right pins? This seems like a software thing to me, not hardware.

“If communications with the lightning chip in the newly-inserted cable fail, and there’s 5 volts on pin 1, go into USB/charge mode”.

2) Note that the maximum power an iDevice may need from a charger is now up to 2A; the newer iPads (if they detect the right voltages on D+ and D-, ie they recognise a capable charger) will suck up 10 watts when they’re in bulk absorption mode, usually when charging from 10-90% of capacity.

This is probably a bit much for a single connection on the lightning connector, hence the need to employ more than one pin for charging. (Again, though, this doesn’t mean a ‘dumb cable fallback’ facility wouldn’t work – just assign more pins to power and ground)

3) The whole “reversible” plug thing – although the pads on top and bottom of the new plug are connected together internally on the cables we’ve seen so far, meaning you couldn’t pass 16 separate signals down it, there’s no reason that future iDevices with larger charge current requirements couldn’t employ a socket that had contacts at top and bottom to double up. Speaking of which, I take it someone’s looked at the sockets and checked whether there are only contacts on one side?

4) Really looking forward to someone getting a buspirate or scope on one of these things so we can see a bit more of what’s going on protocol-wise. It’d be nice to think we’ll be adding Lightning connectors to Arduino projects if we wanted…

By: doubleyou

doubleyou — Tue, 16 Oct 2012 12:23:06 +0000

@Rainer
you may want to update your blog post with the information given here: http://www.chipworks.com/blog/recentteardowns/2012/10/15/inside-the-apple-lightning-cable/
For me the BQ2025 is a simple EPROM that tells the host (e.g. iPhone5) of the lightning connector via SDQ how to configure it’s adaptive pins and what protocol is needed to drive these pins; like USB, I2S for an audio DAC, HDMI for video out etc.

By: someone

someone — Sun, 07 Oct 2012 18:00:39 +0000

“That makes sense in that manufacturing tolerances on the new connector seem to be very tight and critical. Apple certainly wouldn’t want cheap knock-offs of the connector causing shorts, seating loosely or implementing the recognition protocol in a wrong way; this would reflect badly on the devices themselves, just as with apps.

Is the cable (disregarding the chip) a simple, easy to manufacture cable? Yes. Please explain why the currently relevant USB-Lightning cable manufacturing tolerances are somehow more critical than with a normal Micro USB cable?

Will having the chip prevent manufacturing of ‘fake’ cables without (or with faulty) chip? No. So how does the chip save us from those shorts (Is this a problem with USB? No.) and loosely fitting cables?

“Think of this as the App Store for accessory manufacturers. ”"

Think of this as the DRM for accessory manufacturers.

In fact, if they were to release the full specs, we would get fewer badly fitting non-working cables from third party manufacturers, not more…

By: Rainer Brockerhoff

Rainer Brockerhoff — Sat, 06 Oct 2012 00:38:17 +0000

@someone, see update#3 above for my comment on this.

By: someone

someone — Thu, 04 Oct 2012 10:46:39 +0000

“I really see no justification for the “authentication chip” hypothesis”

http://www.theverge.com/2012/10/3/3451032/apple-lightning-certification-accessory-restrictions

I do. It is probably not the only reason for the chip, but it certainly helps in limiting third-party implementations.

By: Steve Weller

Steve Weller — Sun, 30 Sep 2012 03:07:38 +0000

Readers should familiarize themselves with Twisted Pair Ethernet (IEEE 802.3ab) and PoE, aka Power Over Ethernet (IEEE 802.3af-2003) and understand how with 8 pins you can get four signals going both ways at the same time (at 125 MHz), and transmit power from one end of the cable to the other, all the while maintaining isolation and performing negotiation for power and signal capability. Oh, and be able to dynamically adjust for pin reversal and some cabling errors.

Imagine a similar scheme being used by Apple.

By: Chris Porter

Chris Porter — Wed, 26 Sep 2012 22:08:34 +0000

I’m tired of people whining and complaining about having to replace 8-12 cables they supposedly use throughout each day. I understand that it can be frustrating having to replace said cables but they are all a LUXURY or added convenience. I have cables at my desk at home, work, in my car, by the sound board at my church, in my wife’s car, 2 in my backpack, etc. It is very convenient that I have all those old 30-pin cables acquired from who knows where but they are NOT a necessity. I have myself an iPhone 5 and now I just have to actually stop and think if I’m going to be doing something today that would necessitate me bringing my cable along. Is that as convenient as before? Absolutely not. But is it so inconvenient that I need to go by cables…heck no! I’m sure I’ll break down and buy 1 or 2 sometime in the FAR feature but I definitely won’t be replacing them all because they aren’t NEEDED they’re wanted.

The only people that can somewhat complain are ones with installed setups in their automobiles and/or expensive sound docks (i.e. Bose/B&O) But even then Apple has a solution. Is it the most convenient…no…but it is the price you pay for wanting the latest greatest thing.

So, in conclusion people need to stop whining about how inconvenient their lives are now because they have to carry around a cable or put their money where their mouths are and just replace them.