Command Protocol; Data In Commands - Hitachi HTS541010G9AT00 - Travelstar 100 GB Hard Drive Specifications

11.0 Command protocol

The commands are grouped into different classes according to the protocols followed for command execution. The
command classes with their associated protocols are defined below.
Please refer to Serial ATA Revision 1.0a (Section 9. device command layer protocol) and Serial ATA II: Extensions
to Serial ATA 1.0a (Section 4. Command layer) about each protocol.
For all commands, the host must first check if BSY=1, and should proceed no further unless and until BSY=0. For
all commands, the host must also wait for RDY=1 before proceeding.
A device must maintain either BSY=1 or DRQ=1 at all times until the command is completed. The INTRQ signal
is used by the device to signal most, but not all, times when the BSY bit is changed from 1 to 0 during command
execution.
A command shall only be interrupted with a COMRESET or software reset. The result of writing to the Command
register while BSY=1 or DRQ=1 is unpredictable and may result in data corruption. A command should only be
interrupted by a reset at times when the host thinks there may be a problem, such as a device that is no longer
responding.
Interrupts are cleared when the host reads the Status Register, issues a reset, or writes to the Command Register.

11.1 Data In commands

The following are Data In commands:
• Device Configuration Identity
• Identify Device
• Read Buffer
• Read Log Ext
• Read Long
• Read Multiple
• Read Multiple Ext
• Read Sector(s)
• Read Sector(s) Ext
• S.M.A.R.T. Read Attribute Values
• S.M.A.R.T. Read Attribute Thresholds
• S.M.A.R.T. Read log sector
Execution includes the transfer of one or more 512 byte (> 512 bytes on Read Long) sectors of data from the device
to the host.
Note that the status data for a sector of data is available in the Status Register before the sector is transferred to the
host.
If the device detects an invalid parameter, then it will abort the command by setting BSY=0, ERR=1, ABT=1.
Travelstar 5K100 (Serial ATA) Hard Disk Drive Specification
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