Universal Serial Bus (USB)
From HwB
| Line 25: | Line 25: | ||
54321 | 54321 | ||
_______ | _______ | ||
| − | \ | + | \˙˙˙˙˙/ |
----- (at the cable) | ----- (at the cable) | ||
Mini-B: | Mini-B: | ||
| Line 87: | Line 87: | ||
=== Cable === | === Cable === | ||
| − | |||
==== Shielded ==== | ==== Shielded ==== | ||
* Data: 28 AWG twisted | * Data: 28 AWG twisted | ||
Revision as of 15:24, 5 July 2007
Developed by Compaq, Hewlett-Packard, Intel, Lucent, Microsoft, NEC and Phillips.
Contents |
Pinout (Normal)
Series "A" plugs are used towards the host system and series "B" plugs are used towards the USB device.
| Pin | Name | Description |
|---|---|---|
| 1 | VBUS | +5 VDC |
| 2 | D- | Data - |
| 3 | D+ | Data + |
| 4 | GND | Ground |
Pinout (Mini)
Mini-A:
54321 _______ \˙˙˙˙˙/ ----- (at the cable)
Mini-B:
54321 _______ \·····/ ----- (at the cable)
| Pin | Name | Description |
|---|---|---|
| 1 | VBUS | +5 VDC |
| 2 | D- | Data - |
| 3 | D+ | Data + |
| 4 | ID |
|
| 5 | GND | Ground |
Technical specs
Features
- True Plug'n'Play.
- Hot plug and unplug
- Low cost
- Easy of use
- 127 physical devices
- Low cost cables and connectors
Bandwidth
- High speed: 480 Mbps speed (in USB 2.0 and above)
- 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
| Power Gauge | Max length |
|---|---|
| 28 | 0.81 m |
| 26 | 1.31 m |
| 24 | 2.08 m |
| 22 | 3.33 m |
| 20 | 5.00 m |
Cable colors
| Pin | Name | Cable color | Description |
|---|---|---|---|
| 1 | VBUS | Red | +5 VDC |
| 2 | D- | White | Data - |
| 3 | D+ | Green | Data + |
| 4 | GND | Black | Ground |
Contributions
Sources
- USB FAQ at USB Implementers Forum
- USB Specification v2.0 at USB Implementers Forum
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