[Nexus 6P Accessories] Elnrik:
Hi all.

There has been a lot of confusion on the Type-C port on the Nexus devices, all of the different USB specs, how it all relates to charging using USB Type-C devices, and what kind of data speeds you can get from Type-C devices. I did a fair bit of fact finding, and thought I'd consolidate everything I learned into one topic. For now, this is kind of a "living document" in that I am constantly updating the OP to consolidate knowledge. I'm not going to post everything you could ever know about USB specs here, but have provided the links! I am going to try to keep it focused on items as they relate to the new Nexus phones. As always, if you find this helpful, I'd appreciate the thanks.

I feel the state of USB-C cables and charging devices has been fleshed out well enough, and as such, I'm no longer updating this thread.

News:

Good news for consumers! Amazon bans non-compliant USB Type-C cables.

Resources:

https://plus.google.com/+BensonLeung

Reviewed cables: https://plus.google.com/collection/s0Inv

USB Type C Explained: https://plus.google.com/collection/0Vdov

USB Type C News: https://plus.google.com/collection/EKnov

http://www.usb.org/developers/docs/ (Official specifications.)

http://arstechnica.com/gadgets/2015...clear-up-confusion-about-all-these-usb-specs/

http://www.cnet.com/news/usb-type-c-one-cable-to-connect-them-all/

https://en.wikipedia.org/wiki/USB_Type-C

ACTUAL TESTING: http://www.droid-life.com/2015/10/19/nexus-6p-nexus-5x-quick-charge/

https://play.google.com/store/apps/details?id=com.gombosdev.ampere&hl=en

http://xdaforums.com/showpost.php?p=63614861&postcount=91

What rate will my Nexus charge at with other devices?

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When you connect your Nexus to a host, the devices must negotiate which charging rates can be used.

Type C hosts can negotiate with Type C devices using a specific wire in the cable known as the Configuration Channel - aka, the CC wire.

If you are using a Type-A adaptor or cable, the cable must identify itself as a Legacy USB connection (Type-C being converted to Type-A) using a pull-up resistor on the CC wire, grounded to the vBus wire. This is because the CC pin does not exist on Type-A ports. The Nexus will see the resistor, know it is on a legacy port, and it will then perform power negotiation using the USB BC2.1 protocol on the USB 2.0 wires in the cable. If the host is not BC2.1 capable, it will draw default USB current. (See page 149, table 4-12 for order of precedence.)

USB Type-C ports and chargers will provide 5V at 3A (15W) - true fast charging.

USB Type-A ports and chargers using USB BC2.1 should provide a max of 5V at 1.5A (7.5W).

Standard USB 3.0 can provide 5V @ 0.9A (4.5W)

USB 2.0 defaults to 5V @ 0.5A (2.5W).

What this means is that when your phone negotiates power with the host (your charger or computer), whatever current level they mutually agree upon is what your phone will attempt to draw. If you connect to a USB 2.0 port on your computer, a very old port which does not support the BC 2.1 protocol, then the most you'll be drawing is 0.5A. If you connect to a dedicated charging device which supports BC 2.1, it should draw up to 1.5A. Charging rates depend on this negotiation. Out of specification cables do not allow this negotiation to occur correctly. This may lead to faster charging, but you also risk exceeding the capabilities of your charger which may be dangerous.

As you can see, there is a big difference between 15 watts for Type-C fast charging and 2.5 watts for USB 2. Furthermore, please be aware that the phone will pull less current as the battery charges. A Nexus at 80% battery will pull less current than a Nexus at 20% battery.

In any regard, consider USB Type A to be the weak link in charging your Nexus.

Table 4-12:

View attachment 3501594

What charger and cable will work with my new Nexus, and will it support fast charging?

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My suggestion would be to make the move to Type-C car and wall chargers. You will eliminate the chance of using out of specification Type-A cables, and ensure you are always fast charging. Type-C will soon be the de facto interface for USB, so why not future proof yourself now.

If you have to use Type-A adaptors and cables, understand that there will be limitations and concerns to be aware of. Out of specification cables being the primary issue, which is explained below. Further, your charging rates will be half (or less) than what Type-C is capable of.

Table 2-1 shows all supported power specs for Type-C charging. Please understand that Type-A ports/cables will only support up to the BC 2.1 charging level of 1.5A. If it goes beyond this, your cable may not be compliant with USB specifications.

View attachment 3501592

As referenced in the quote, Table 4-13:

View attachment 3529027

What about QuickCharge 2.0/3.0 chargers!? My Nexus has a Qualcomm chip, isn't it compatible?

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No. Google has stated that it is not implemented in the new Nexus devices.

QuickCharge works by increasing voltage and amperage to charge quickly. The USB Type-C standard only works this way in USB PD modes, otherwise voltage never varies from 5V. This means that

QuickCharge 2.0/3.0 is completely different from USB Type-C charging methods.

But my 2.4A rated Type-A charger works, and my phone says it is Fast Charging. What's the deal?

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Your Nexus may report as fast charging if the Type-A cable you use is not compliant with USB specs.

Threads on this forum have confirmed that the phone will pull 3A (or about 2990mA) from the stock charger. These results were verified using apps such as Ampere. When using 3rd party equipment (non-OEM cables and chargers), I would suggest using an application such as Ampere to ensure that you are not exceeding the maximum rating of the charger or cable. Doing so can be dangerous! It will also verify exactly how much current your phone is pulling to charge - information I've found helpful if for no other reason than to satisfy my own curiosity.

If you are unsure if your cable is compliant, you can test it using the methods found here: http://www.androidheadlines.com/201...usb-type-c-for-nexus-5x-6p-compatibility.html

So, how should you approach charging and connecting your Nexus to other devices?

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The same way you would any other device - plug it into the best thing you have available.

For connecting to computers, use the best port you have available. Type-C to Type-C > USB 3.x to Type-C > USB 2 to Type-C.

For chargers, try to match OEM specs: 5 volts at 3 amps output using a Type C connector.

If you have to use an adapter (Type-A to Type-C), Make sure you use compliant cables!

What data connection speeds will I get on my Nexus using Type-C?

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If you want to dig deep into this, look at the "USB Type-C Specification Release 1.1.pdf" doc from USB.org, it defines on page 19 the types of plugs and cables for Type-C, including the USB 2.0 Type-C port. Starting at page 57 it defines all of the wires/pins for the different cables. Comparing table 3-10 to 3-11, you can see that all of the SDP (shielded differential pair) signal pins/wires are missing in the USB 2.0 Type-C connections. These are your high speed data connection wires. The Vbus, Vconn, cc, GND wires are all still present to support Type-C power delivery.

So, in other words, there are USB 2.0 Type-C ports, and USB 3.0 ports. For devices which don't require up to 100 watts of power, or won't use up to 10GB/s transfer speeds, the USB-C 2.0 port may commonly be used. The Nexus 5X & 6P fall into this category. What connection speeds are you going to get with the Nexus?

USB 2.0 speeds.

Full Featured USB Type-C Cable:

View attachment 3564175

USB 2.0 Type-C to Type-A cable:

View attachment 3564176

If I left any glaring omissions from this, please follow up. I'd love to have all the info we can get.

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I wanted to put in this addition to the op. Thanks to [MENTION=788304]aaron_huber[/MENTION] for putting this information up.

Aaron said:

A wire is a wire, but in this case the magic is in the charger, the device, AND THE CABLE. From the USB-C Wikipedia page:

Full-featured USB Type-C cables are active, electronically marked cables that contain a chip with an ID function based on the configuration data channel and vendor-defined messages (VDMs) from the USB Power Delivery 2.0 specification. USB Type-C devices also support power currents of 1.5 A and 3.0 A over the 5 V power bus in addition to baseline 900 mA; devices can either negotiate increased USB current through the configuration line, or they can support the full Power Delivery specification using both BMC-coded configuration line and legacy BFSK-coded VBUS line.

The 6P does not support the full PD spec per Google, but it does use the "configuration line" which is an extra wire in the USB-C cable hooked up to an extra pin in the phone/charger to talk to the charger and negotiate extra current. If you don't have a USB-C cable with the extra pins/wires plugged into a USB-C charger on the other end that also has the extra pins to do the negotiation, then the phone will fall back to a lower current because the spec requires it. If you plug it into a USB-A charger or use a USB-A to USB-C cable then all you get are four wires -

the "configuration line" to do the negotiation doesn't exist

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* Type-C capabilities exceeds previous USB Type-A 3.1 / 2.0 specifications:

** 2 way power transfer

** Universal plug type (reversible plug)

** Much high transfer speeds (10GB/s)

** Much higher charging capabilities (Up to 20V@5A = 100W via USB PD)

** Alternate data modes for devices (Display port / Audio)

Known Type-C capabilities for Nexus 5x & 6P:

+ USB 2.0 Data transfer speeds

+ Full fast charging through USB Type-C ports or specifically designed 5v/3a capable Type-C chargers only

- Not Qualcomm QuickCharge compatible (may draw more current for charging than a standard USB port though, see below)

- No HDMI out (It is not type-c alternate mode capable.)

- Not USB-PD capable

Thanks all!