3.2.7.2 USB Interfaces

The USB (Universal Serial Bus) is a hot-pluggable general-purpose high-speed I/O standard for computer peripherals. The standard defines connector types, cabling, and communication protocols for interconnecting a wide variety of electronic devices. The USB 2.0 Specification defines data transfer rates as high as 480 Mbps (also known as High Speed USB). A USB host bus connector uses 4 pins: a power supply pin (5V), a differential pair (D+ and D- pins) and a ground pin.

The baseboard features three USB communication ports named USB-A to USB-C:

• USB-A device interface
  • One USB device standard micro-AB connector.
  • This port offers a VBUS detection function through the R81-R83 resistor ladder.
  • The USB-A port is used as a secondary power source and as a communication link for the baseboard, and derives power from the PC over the USB cable. In most cases, this port is limited to 500 mA.
• USB-B (host port B high- and full-speed interface)
  • One USB host type C connector.
  • The USB-B host port is equipped with a 500 mA high-side power switch.
• USB-C (High-Speed Inter-Chip/HSIC port)
  • One USB high-speed host port with an HSIC interface.
  • The port is connected to a single 2-pin header (not populated).