USB TYPE-C和USB2.0 TYPE-B插头线缆接线图

1. Pin A5 (CC) of the USB Type-C plug shall be connected to GND through a resistor Rd (5.1 kΩ ± 20%).
   See Section 4.5.3.2.1 and Table 4-25 for the functional description and value of Rd.
2. Contacts B6 and B7 should not be present in the USB Type-C plug.
3. All VBUS pins shall be connected together within the USB Type-C plug. Bypass capacitors are not
   required for the VBUS pins in this cable.
4. All Ground return pins shall be connected together within the USB Type-C plug.
5. Shield and GND grounds shall be connected within the USB Type -C and USB 2.0 Standard-B plugs on
   both ends of the cable assembly.
6. All USB Type-C plug pins that are not listed in this table shall be open (not connected).

USB信号定义：http://www.usbzh.com/article/detail-206.html
USB接口大全：http://www.usbzh.com/article/detail-144.html
TYPE-C信号定义：http://www.usbzh.com/article/detail-722.html