4.1. USB Class

关于USB的Class,对于学习USB协议的人,估计早就听到过此名词了。

而对于USB的Class的分类,此处先列出那个最基本的分类表:

表 4.1. USB Class表

Base ClassDescriptor UsageDescription
00hDevice Use class information in the Interface Descriptors
01hInterfaceAudio
02hBothCommunications and CDC Control
03hInterfaceHID (Human Interface Device)
05hInterfacePhysical
06hInterfaceImage
07hInterfacePrinter
08hInterfaceMass Storage
09hDeviceHub
0AhInterfaceCDC-Data
0BhInterfaceSmart Card
0DhInterfaceContent Security
0EhInterfaceVideo
0FhInterfacePersonal Healthcare
DChBothDiagnostic Device
E0hInterfaceWireless Controller
EFhBothMiscellaneous
FEhInterfaceApplication Specific
FFhBothVendor Specific


再回到上述的表 4.1 “USB Class表”,其中的“Descriptor Usage”中的Interface,Device等,对应的是来自表 4.2 “USB Descriptor Type”

表 4.2. USB Descriptor Type

Descriptor TypeValue
DEVICE1
CONFIGURATION2
STRING3
INTERFACE4
ENDPOINT5
DEVICE_QUALIFIER6
OTHER_SPEED_CONFIGURATION7
INTERFACE_POWER8


而关于什么是Device,什么是Interface等内容,暂时先简述他们之间的关系:

Device ⇒ Configuration ⇒ Interface ⇒ Endpoint

更新详细内容,待以后有空再深入解释。