Mass storage implementation

ST72681

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5.3.1

Public drive

The public drive is the default configuration in a mono-LUN mode. In this default case, it is

declared as a removable drive.

The public drive is mandatory and can not be removed from the configuration. By

customization (using PC software), it can be declared as a removable drive, a CD-ROM

drive or a hard disk drive.

This drive is the LUN 0 in BOT commands.

5.3.2

Private drive

The Private drive is optional. Its type is “removable drive” and is not configurable.

This drive is protected by password and cannot be directly accessed through the PC

operating system. A PC software tool is necessary to send a command with the password to

unlock the device. The device is then open and accessible by the PC operating system until

reset or reception of a new command to lock the drive.

This drive is the LUN 1 in BOT commands.

5.3.3

Additional drive

The additional drive is optional. Its type can be “removable drive”, “hard disk drive” or “CD-

ROM drive”.

This drive is LUN 1 in BOT commands if the private drive option is not active, and is LUN 2 if

the private drive option is active.

5.3.4

CD-ROM considerations

When a drive is declared as CD-ROM, the ST72681/R21 manages this drive with a logical

block size of 2 Kbytes. To be correctly recognized by the host, it is preferable to build a

CDFS partition on this CD-ROM. See the ‘ST7268x Production Tool User Manual’ for more

information.

Note that the ST72681/R20 doesn’t consider the CD-ROM partition as a specific case. The

logical block size is 512 bytes and any file system can be used.

In both cases, the CD-ROM partition allows the use of the autorun operating system feature.

During device connection, the CD-ROM partition is recognized and the host tries to run the

application corresponding to the ‘autorun.inf’ file present into this CD-ROM partition.

5.4

Mass storage interface configuration

In addition to the parameters already described as configurable in the previous chapters,

additional customizable information includes:

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USB parameters: VID, PID, all string information

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SCSI parameters: strings for inquiry commands