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发表于 2003-3-5 09:43:00
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可能有用。
Pin Name Description
1 VCC +5 VDC
2 D- Data -
3 D+ Data +
4 GND Ground
有关的技术说明：
Universal Serial Bus (USB) (Technical)
USB was developed by Compaq, Digital Equipment Corp, IBM PC Co., Intel, Microsoft, NEC and Northern Telecom.
Features:
?True Plug'n'Play.
?Hot plug and unplug
?Low cost
?Easy of use
?127 physical devices
?Low cost cables and connectors
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
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 VCC Red +5 VDC
2 D- White Data -
3 D+ Green Data +
4 GND Black Ground |
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