2
Brief Introduction to USB 2.0
f Four wire system (D+, D-, VBUS, GND)
f USB2.0 provides the following speed selections
f Self powered and Bus powered devices VBUS supplies power to devices that driver their primary power from
the host or hub.
f The USB-IF has instituted a certification and marking program
– Persuade developers to fully test their USB devices.
– New USB trademark logo that indicates a device is certified and conforms to all applicable USB 2.0 specifications.
500 ps480 MbpsHigh Speed
4 – 20 ns
12 MbpsFull Speed
75 to 300 ns1.5 MbpsLow Speed
Rise TimeData Rate
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