Type C USB

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recri

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I've been musing over the Type C USB connector on my Chromebook. I watched a 40 minute video at Cypress this morning, http://www.cypress.com/?rID=111101, and I've downloaded the USB Type C documents http://www.usb.org/developers/usbtypec/, but I'm still at the earliest stages of exploring this.

There are three devices with USB Type C connectors on the market this week, a MacBook, a ChromeBook, and a Nokia Tablet. There will be dozens by the end of the year. There are several advantages to USB Type C: 1) there's no right side up for the plugs, they connect either side up; 2) there's no wrong end on the cable, they're the same on both ends; 3) either end of a Type C cable can supply power to the other end, and they can swap roles, too; 4) the power supplied can be negotiated up to 100W, 5A @ 20V; 5) in addition to the USB 2.0 data lines, there are four super-speed differential pairs, and a bunch of other signals; 6) one use for those super-speed pairs is video, the Chromebook has display port and hdmi adapters; 7) and so on, ....

I believe that a Type C USB connector could be connected to a Teensy and with a few pullups and pulldowns on the configuration channels pins, the Teensy could passively request several power configurations. The GND, VBUS, and USB 2.0 data lines would connect straight through. All the other USB 3.x super-speed lines would be ignored.

It also seems likely that the Teensy could actively participate on the configuration channel and negotiate even more power configurations or change its role. It needs to handle 300 kHz Manchester BPSK superimposed on DC supplied to power the configuration controller. I'm not sure exactly what that means, yet, but I see an arduino manchester coding packages that use one pin for transmit and one for receive, so I suspect we're basically looking for clock transitions. And I think the physical interface is a just a transformer to isolate the coding AC from the power DC. If more than a 5V supply were requested, then we'd need a step down regulator to power the Teensy, or could it power from the Vconn configuration channel?

http://www.cypress.com/ccg1/ and http://www.cypress.com/ccg2/ are Cypress dedicated controllers, which could be spliced between the Type C connector and the Teensy. But I suspect the Teensy 3's could handle it all themselves, and maybe there could be a Teensy 3.xC that only changed the connector and a few traces? Or could the MINI54TAN handle this?

The reason for wanting this is to send more power to the Teensy. If you're driving LED arrays, motors, speakers, or a radio transmitter, life is so much easier if you can pull power over the same cable. And if you're distributing power to Teensy driven hardware, it's also nice to be able to watch both ends of the negotiation.

-- rec --
 
seems to me that you'd be best served with a breakout board. I doubt it makes much sense for the Teensy motherboard to be designed to handle up to 100W of power. However, I see no reason that an external board that the Teensy is plugged into could not do that. That said, I doubt we will see laptops on battery power supplying that kind of power (seems like a very expensive way to do it) vs. simply having a honking power supply for the LEDs, a small well-regulated one for the Teensy, and a shared ground.
 
When I made Teensy++ 2.0, years ago, the situation was similar with Micro-B. The connector was very new. I put the question out to many people, should we switch or stay with Mini-B. At the time, few Micro-B cables were on the market. Those that did exist were much more expensive. The connectors were also very new and difficult to get, and cost more. By the time Teensy 3.0 was designed, Micro-B had become mainstream. Cables were about the same price and readily available.

The situation with Type C is the same. It's just too early. Like Micro-B, eventually we'll end up using it, probably in a year or two. The main indicator to look for is the price of Type C cables.
 
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Yeah, I was checking the prices of USB-C connectors at Digikey, the one's in stock are $4.69 a piece at the moment, and there are 3000 in stock. In comparison a micro-B connector is $0.76 a piece and there are 100,000 in stock. (But I also found a 2 meter USB-A-male to USB-B-male cable for $49.98 277-2655-ND, it does USB 2.0 and it's shielded! So don't believe all the cable prices you see).

100W would be a lot, but it would probably come from a powered USB-C hub that's also powering the computer rather than from the computer itself. But there are a lot of use cases between there and the 2.5W the Teensy is currently supporting. 2 or 3A at 5V makes a lot more possible than 0.5A. And all of this will need to route the additional power off the Teensy, there's nothing on the board that could use the power nor is there room for traces to carry that much current.

The power brick that came with my Chromebook is rated 3A @ 20V, 12V, 5V. It can only deliver one of those voltages at a time. A smart powered USB-C hub could take power from multiple bricks.

...

I've restudied some of the materials. It appears that there will be plain, fancy, and very fancy USB-C cables. The plain will do USB-2.0 and be able to deliver 3A @ 5V. The downward facing port, the power supplier, marks its maximum current capacity in the pull-ups on the configuration channels. It seems that there must be another step here, where the upward facing port, the power sink, signals its requirements, but I don't see where it happens, yet.

To get more than 3A you'll need a 5A rated cable, for one thing, and you'll need to run a configuration channel to find out if the supplier can do 5A and to request 5A. You'll also need to run a configuration channel to boost the power to 12V or 20V at any current.

To be a fancy USB-C cable you need to have configuration controllers embedded in the controllers to ensure that the super-speed lanes get muxed onto the correct pins at both ends. The very fancy cables reorganize the cable lanes into something else altogether, and this is how the display port and hdmi adapters work.

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This is the third or fourth edit of this before posting. So I see that HP has announced a new convertible tablet with a Type-C power supply.

-- rec --
 
USB Type-C is definitely becoming more commonplace.
My Google Nexus 6P android phone has it as well as the 5X. It's rumored that the next generation Nexus' will continue to use USB Type-C
Additionally, RavPower makes a line of wall wart chargers and Mobile power banks that support USB Type-C
 
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