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
5 pin mini-USB plug connector at the peripherals.
5 pin mini-USB jack connector at the controller.
|X||ID||May be N/C, GND or used as an attached device presence indicator (shorted to GND with resistor).|
Mainboard USB Connector
10 pin IDC male connector at the motherboard
|1||VCC||+5 VDC||USB 1|
|2||VCC||+5 VDC||USB 2|
- True Plug’n’Play.
- Hot plug and unplug
- Low cost
- Easy of use
- 127 physical devices
- Low cost cables and connectors
- Keyboards, mice, joysticks, modems
- Full speed: 12 Mbps speed (requires shielded cable)
- Low speed: 1.5 Mbps speed (non-shielded cable)
USB Host = The computer, only one host per USB system. USB Device = A hub or a Function.
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
- 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.
Shield should only be connected to Ground at the host. No device should connect Shield to Ground.
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
|Power Gauge||Max length|
To force charging of your iPod, PSP or any USB device, you have to force high the levels of the data pins 2 (D-) and 3 (D+) by connecting them to a +5V using a 10KOhm resistor.