USB C to USB A pinout

It's the D+ and D- like normal. There is two of each because USB C is supposed reversible. You can insert the plug both ways and it will still be a valid USB 2 connection, as usb 2.0 does not negotiate the pinning. Flip the plug 180 degrees and the same pins will connect in the same order. Your board should connect both together for maximum connectivity.

There is no ID pin, as that's only implemented on plugs. In USB C, the CC pins handle this, and pulling them to ground with a 5K resistor will initiate OTG HOST mode on the other side of the link.


If you are fitting an old style USB 2.0 device with new Type-C connector, you need:

(a) connect A6 with B6;

(b) connect A7 with B7;

(c) connect EACH CC1 and CC2 to ground with 5.1k resistor.

All legacy Type-C cables have only one D+/D- signal pair in the cable, so you need (a) and (b). [as a matter of fact, contacts B6 and B7 are absent in the Type-C plug. So the receptacle must have A and B connected]. There is also only one CC wire in the cable, so pull-downs and sensors must be on both CC1 and CC2 in the device.

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