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USB interface

USB connector


The left figure shows the terminals of a USB connector. This is USB-Type-A male connector. This connector is the common type used for connection with PC.
The pinout description which viewed from connector side is GND(Ground for voltage), +DATA(Output from computer), -DATA(Input to computer) and +5V from the left.
The case of a connector is connected to the shield wire of the cable and grounded by the equipment side.

Specification of USB
ItemsUSB1.1USB2.0
Low-speedFull-speedHigh-speed
Transfer rates1.5Mbps12Mbps480Mbps
Max number of endpoints215-
Transfer mode/
Packet size(B)
Control1 - 81 - 641 - 64
Interrupt1 - 81 - 641 - 3,072
Bulk-1 - 641 - 512
Isochronous-1 - 1,0231 - 3,070

The USB driver IC which used in this time supports USB Ver1.0 and 1.1. High-speed communication is possible for Ver2.0 but it doesn't use in this time.
I will explain the specifications for Ver 1.0 and 1.1 below. However, the contents to explain are not detailed. Please read some technical books, if you want to know more things.