ST72681

Mass storage implementation

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5

Mass storage implementation

5.1

USB characteristics

The ST72681 is compliant with USB 2.0 specification.

It is able to operate in both high speed and full speed modes using a bidirectional control

endpoint 0 and a bidirectional bulk endpoint 2.

It automatically recognizes the speed to use on the bus by a process of negotiation with

USB Host.

5.2

BOT / SCSI implementation

5.2.1

BOT specification

The USB Mass Storage Class Bulk Only Transport (BOT) specification version 1.0 is

implemented. It allows the device to be recognized by the host as a mass-storage USB

device.

5.2.2

SCSI specification

Moreover, inside BOT transfers, SCSI commands are encapsulated for mass storage

operations.

The related specifications are SBC-2 revision 10 (SCSI Block Commands 2) and SPC-4

revision 7a (SCSI Primary Commands 4).

5.2.3

Bootability specification

The USB Mass Storage Specification for Bootability revision 1.0 is implemented.

It allows the PC host to boot the operating system from the USB mass storage application.

In this case, the Host uses BOT LUN 0 (logical unit number).

A specific tool must be used to format the logical drive in order to make it bootable by

programming the correct information.

5.3

Multi-LUN device characteristics

The application can be configured with a dedicated PC software tool as a multi-LUN device.

In this case, up to 3 different drives are available: public drive, additional drive and private

drive.

Public and additional drives can be configured as removable drive, hard disk drive or CD-

ROM drive.