[Arm-netbook] USB3.1 pinout

Internet internet at devpi.de
Sun Feb 5 21:30:04 GMT 2017

On Feb 5, 2017, 15:06, at 15:06, Julius Lehmann <julius at devpi.de> wrote:
>Regarding USB C you are right that there are four differential pairs on
>the connector. However, for communication only two pairs are used
>because the USB 3.1 protocol only uses two. On the device that has a
>USB C connector you need a dedicated controller that manages the
>orientation of the plug. Then the two data lines are connected to the
>right pins on the connector through a multiplexer. The other two pairs
>on the connector are for no use in USB mode but if you want to use USB
>C in alternate mode (e.g. DisplayPort), signals can be rerouted.
>You can find all the information on usb.org (zip archive with full
>This basically means that the EOMA68 standard has two differential
>pairs that are not used for USB but if your intention was to make it
>available for USB C, an internal multiplexer would be needed.
>Kind regards
>Julius Lehmann
>On Feb 5, 2017, 14:20, at 14:20, Luke Kenneth Casson Leighton
><lkcl at lkcl.net> wrote:
>>crowd-funded eco-conscious hardware:
>>On Sun, Feb 5, 2017 at 11:44 AM, Internet <internet at devpi.de> wrote:
>>> Hey there!
>>> I was wondering about the USB3.1 pinout in the EOMA68 standard. In
>>> research on the USB Type C connector I found out that USB3.1
>>> (Superspeed+) has only two differential signal pairs (one for
>>> one for transmitting)
>>two for receiving, two for transmitting, each 5gbit/s for a total of
>>10gb/sec.  the connector and thus the pinouts are rotatable by 180
>>degrees so the pinouts on the first 12 pins (top row) are *identical*
>>layout to the second 12 pins (bottom row) except in the reverse order.
>>D+ and D- (the USB2 pins) are *missing* on one row of the receptacle
>>so that you don't connect them up twice (which would be bad).
>>you *may* be thinking of USB 3.0 which is connector-compatible with
>>USB 2.0 and is what you find on most laptops and desktop computers
>>these days:
>>that is *only* one set of (5gbit/sec) tx-rx differential pairs.
>>scared me for a minute that i'd messed it up... :)
>>arm-netbook mailing list arm-netbook at lists.phcomp.co.uk
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