Mass Storage Device Class
Descriptors
- Only uses standard interface descriptors
- for Bulk Only Transport, BOT
- for Control/Bulk/Interrupt Transport, CBI
Requests
- for BOT
- Mass Storage Reset
- Get Max LUN
- Devices that do not support multiple LUNs may STALL this command.
- LUN: Logic Unit Numbers (0~15)
- If the device supports four LUNs then the LUNs would be numbered from 0 to 3 and the return value would be 3.
- for CBI
- Accept Device-Specific Command (ADSC)
Composition of BOT
Command/Data/Status Protocol
command transport, data transport, status transport
CBW: Command Block Wrapper
CSW: Command Status Wrapper
CBW -> Data -> CSW
- USB Floppy Interface, UFI
- occupies CBWCB, the last field of CBW