[Arm-netbook] USB3.1 pinout

[Internet]

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
>specification).
>
>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:
>https://www.crowdsupply.com/eoma68
>>
>>
>>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
>my
>>> research on the USB Type C connector I found out that USB3.1
>>> (Superspeed+) has only two differential signal pairs (one for
>>receiving,
>>> one for transmitting)
>>
>>http://pinoutguide.com/Slots/usb-type-c_pinout.shtml
>>
>>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:
>>
>>http://pinoutguide.com/Slots/usb_3_0_connector_pinout.shtml
>>
>>that is *only* one set of (5gbit/sec) tx-rx differential pairs.
>>
>>scared me for a minute that i'd messed it up... :)
>>
>>l.
>>
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