Piedinature - Pinouts
USB - Universal Serial Bus

Reference and Sources:

• Universal Serial Bus Implementers Forum Home Page
• USB FAQ
• Texas Instruments USB Specification
• USB Design by Example - selected USB documents
• USB Central - links to information about USB and sample code to download

USB was developed by Compaq, Digital Equipment Corp, IBM PC Co., Intel, Microsoft, NEC and Northern Telecom.
Becoming standard on motherboards, OS support standard with Microsoft Windows® 95 (OSR 2). Provides power through cable. Has hot-plugging capability.

4 Pin Male "A" Connector on the cable

4 Pin Female "A" Connector on the computer

4 Pin "B" Male Connector on cable

4 Pin "B" Female Connector on computer

Features:

• True Plug'n'Play.
• Hot plug and unplug
• Low cost
• Easy of use
• 127 physical devices
• Low cost cables and connectors

Uses:

• Keyboards, mice, joysticks, modems

Bandwidth:

• Full speed: 12 Mbps speed (requires shielded cable)
• Low speed: 1.5 Mbps speed (non-shielded cable)

Definitions:

USB Host = The computer, only one host per USB system.
USB Device = A hub or a Function.

Power usage:

Bus-powered hubs: Draw Max 100 mA at power up and 500 mA normally.
Self-powered hubs: Draw Max 100 mA, must supply 500 mA to each port.
Low power, bus-powered functions: Draw Max 100 mA.
High power, bus-powered functions: Self-powered hubs: Draw Max 100 mA, must supply 500 mA to each port.
Self-powered functions: Draw Max 100 mA.
Suspended device: Max 0.5 mA

Voltage:

• Supplied voltage by a host or a powered hub ports is between 4.75 V and 5.25 V.
• Maximum voltage drop for bus-powered hubs is 0.35 V from it's host or hub to the hubs output port.
• All hubs and functions must be able to send configuration data at 4.4 V, but only low-power functions need to be working at this voltage.
• Normal operational voltage for functions is minimum 4.75 V.

Shielding:

Shield should only be connected to Ground at the host. No device should connect Shield to Ground.

Cable:

Shielded:
Data: 28 AWG twisted
Power: 28 AWG - 20 AWG non-twisted

Non-shielded:
Data: 28 AWG non-twisted
Power: 28 AWG - 20 AWG non-twisted

Cable colors: