USB Mass Storage Command Protocol

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USB Mass Storage Command
Protocol

• B93902019 ???
• B93902101 ???

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Introduction

• A UFI Device is a removable-media mass storage
  subsystem.
• Connects to a Host computer via its Universal
  Serial Bus(USB) port.
• Use Command Blocks.
• USB Floppy Disk Unit(USB FDU)

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Introduction(Cont.)
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UFI Commands

• Each command block is 12 bytes in length.
• Bulk-in Endpoint
• Bulk-out Endpoint

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UFI Commands(Cont.)
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UFI Commands(Cont.)

• UFI Command Block Description

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UFI Commands(Cont.)
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UFI Commands(Cont.)

• Status
• Immediate Command Processing Considerations
• UFI Command Process Flow
• Aborting an UFI Command

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Sense Data

• UFI device stores the execution result status of
  every command block as Sense Data.

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Sense Data(Cont.)
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Sense Data(Cont.)
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UFI Command Descriptions
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FORMAT UNIT Command

• Physically format one track of a diskette
  according to the selected options.

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FORMAT UNIT Command(Cont.)
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FORMAT UNIT Command(Cont.)
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FORMAT UNIT Command(Cont.)
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INQUIEY Command

• Request the information regarding parameters of
  the UFI device itself be sent to the host.
• Used by a driver on the host to ask the
  configuration of the UFI device.
• Typically after power-on or hardware reset.

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INQUIRY Command(Cont.)
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INQUIRY Command(Cont.)
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MODE SELECT Command

• The MODE SELECT command allows the host to
  specify medium or device parameters to the UFI
  device.

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MODE SELECT Command(Cont.)
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MODE SENSE Command

• The MODE SENSE command allows the UFI device to
  report medium or device parameters to the host.

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MODE SENSE Command (Cont.)
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Mode Select / Mode Sense Parameters
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PREVENT-ALLOW MEDIUM REMOVAL Command

• This command tells the UFI device to enable or
  disable the removal of the medium in the logical
  unit.

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PREVENT-ALLOW MEDIUM REMOVAL Command (Cont.)
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PREVENT-ALLOW MEDIUM REMOVAL Command (Cont.)

• Prevent prevent media removal flag
• 0 enable (allow) the removal of the medium
• 1 disable (prevent) removal of the medium

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READ(10) Command

• The READ(10) command requests that the UFI device
  transfer data to the host.

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READ(10) Command (Cont.)
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READ(12) Command

• The READ(12) command requests that the UFI device
  transfer data to the host. The most recent data
  value written in the addressed logical block on
  the medium shall be returned.

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READ(12) Command (Cont.)
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READ CAPACITY Command

• The READ CAPACITIY command allows the host to
  request capacities of the currently installed
  medium.

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READ CAPACITY Command (Cont.)
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READ CAPACITY Command (Cont.)
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READ FORMAT CAPACITIES Command

• The READ FORMAT CAPACITIES command allows the
  host to request a list of the possible capacities
  that can be formatted on the currently installed
  medium.

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READ FORMAT CAPACITIES Command (Cont.)
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READ FORMAT CAPACITIES Command (Cont.)

• Allocation Length specifies the maximum number
  of bytes of format data the Host can receive.

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READ FORMAT CAPACITIES Command (Cont.)

• Capacity List
• Upon receipt of this command block, the UFI
  device returns a Capacity List to the host on the
  Bulk In endpoint.
• No media in FDU Capacity List Header Maximum
  Capacity Header
• Media in FDU Capacity List Header Current
  Capacity Header Formattable Capacity
  Descriptors

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READ FORMAT CAPACITIES Command (Cont.)
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READ FORMAT CAPACITIES Command (Cont.)
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READ FORMAT CAPACITIES Command (Cont.)
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READ FORMAT CAPACITIES Command (Cont.)
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READ FORMAT CAPACITIES Command (Cont.)
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READ FORMAT CAPACITIES Command (Cont.)
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READ FORMAT CAPACITIES Command (Cont.)
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READ FORMAT CAPACITIES Command (Cont.)
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REQUEST SENSE Command
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REZERO UNIT Command
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SEEK Command
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SEND DIAGNOSTIC Command
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START-STOP UNIT Command
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TEST UNIT READY Command
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VERIFY Command
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WRITE(10) Command
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WRITE(12) Command
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WRITE AND VERIFY Command
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