5K320 SATA OEM Specification
13 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 2.6 (Section 11. device command layer protocol) 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.
“Table 139 Timeout Values” on Page 175 shows the device timeout values.
13.1 Data In Commands
These commands are:
Device Configuration Identify
Identify Device
Read Buffer
Read Log Ext
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.
If an error occurs, the device will set BSY=0, ERR=1, and DRQ=1. The device will then store the error status in the Error Register. The registers will contain the location of the sector in error. The erroneous location will be reported with CHS mode or LBA mode, the mode is decided by mode select bit (bit 6) of Device register on issuing the command.
13.2 Data Out Commands
These commands are:
Device Configuration Set
Download Microcode
Format Track
Security Disable Password
Security Erase Unit
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