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 Class | Descriptor Usage | Description |
---|---|---|
00h | Device | Use class information in the Interface Descriptors |
01h | Interface | Audio |
02h | Both | Communications and CDC Control |
03h | Interface | HID (Human Interface Device) |
05h | Interface | Physical |
06h | Interface | Image |
07h | Interface | Printer |
08h | Interface | Mass Storage |
09h | Device | Hub |
0Ah | Interface | CDC-Data |
0Bh | Interface | Smart Card |
0Dh | Interface | Content Security |
0Eh | Interface | Video |
0Fh | Interface | Personal Healthcare |
DCh | Both | Diagnostic Device |
E0h | Interface | Wireless Controller |
EFh | Both | Miscellaneous |
FEh | Interface | Application Specific |
FFh | Both | Vendor 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 Type | Value |
---|---|
DEVICE | 1 |
CONFIGURATION | 2 |
STRING | 3 |
INTERFACE | 4 |
ENDPOINT | 5 |
DEVICE_QUALIFIER | 6 |
OTHER_SPEED_CONFIGURATION | 7 |
INTERFACE_POWER | 8 |
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。