5.3 Host Commands
C141-E042-01EN 5-55
Features Resister Function
X’DA’ SMART Return Status:
When the device receives this subcommand, it asserts the BSY bit and saves
the current device attribute values. Then the device compares the device
attribute values with insurance failure threshold values. If there is an
attribute value exceeding the threshold, F4h and 2Ch are loaded into the CL
and CH registers. If there are no attribute values exceeding the thresholds,
4Fh and C2h are loaded into the CL and CH registers. After the settings for
the CL and CH registers have been determined, the device clears the BSY bit
The host must regularly issue the SMART Read Attribute Values subcommand
(FR register = D0h), SMART Save Attribute Values subcommand (FR register =
D3h), or SMART Return Status subcommand (FR register = DAh) to save the
device attribute value data on a medium.
Alternative, the device must issue the SMART Enable-Disable Attribute
AutoSave subcommand (FR register = D2h) to use a feature which regularly save
the device attribute value data to a medium.
The host can predict failures in the device by periodically issuing the SMART
Return Status subcommand (FR register = DAh) to reference the CL and CH
registers.
If an attribute value is below the insurance failure threshold value, the device is
about to fail or the device is nearing the end of it life . In this case, the host
recommends that the user quickly backs up the data.
At command issuance (I-O registers setting contents)
1F7
H
(CM) 10110000
1F6
H
(DH)
×××
DV xx
1F5
H
(CH)
1F4
H
(CL)
1F3
H
(SN)
1F2
H
(SC)
1F1
H
(FR)
Key (C2h)
Key (4Fh)
xx
xx
Subcommand