hello today let's learn something about USB bus

USB bus is a general purpose serial bus

allows external devices to be hot plugged

well powered on

common USB buses include USB 2.0

USB 3.0 etc for example

like this USB interface

it distributes the USB 2.0 and the USB 3.0 buses

we call it USB 3.0 interface

at the same time

the USB 2.0 bus also connects other peripherals

like camera Bluetooth and so on

USB 2.0 bus is a 2 way communication

directly connected to the PCH

chip from the USB interface

these 2 lines are USB 2.0 bus

it consists of a positive data and a negative data

here 4 lines belong to the USB 3.0 bus

the following 2 are a pair of sending signal lines

it goes to the USB interface through the coupling

capacitor and communicates with the USB device

this pair of receiving signal lines

does not require coupling capacitors for communication

it is also directly connected to the PCH chip

only this pair of transmit signals

needs to communicate through the coupling capacitor

this is the USB 2.0 and USB 3.0 bus

USB 3.1 generation one actually refers to USB 3.0

USB 3.1 generation 2 is the real USB 3.1

the maximum transfer bent with of early USB 2.0 was

480 megabits

when it comes to USB 3.0

its maximum transmission banned with is 5.0GB

then it comes to USB 3.1 generation 2

its maximum transmission

banned with can theoretically reach 10GB

but it actually reserved some bandwidth to support

other functions

so its actual effective bandwidth is about 7.2 GB

USB 3.1 generation 2

is fully downward compatible

with the existing USB connectors and cables

this is the USB bus