| Table 5.7 Features Register values (subcommands) and functions | |
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Features Resister |
| Function |
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X’D0’ |
| SMART Read Attribute Values: |
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| A device that received this subcommand asserts the BSY bit and saves all the |
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| updated attribute values. The device then clears the BSY bit and transfers |
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| attribute value information to the host. |
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| * For information about the format of the attribute value information, see Table 5.8. |
X’D1’ |
| SMART Read Attribute Thresholds: |
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| This subcommand is used to transfer |
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| to the host. |
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| * For information about the format of the insurance failure threshold value data, see |
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| Table 5.9. |
X’D2’ |
| SMART |
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| This subcommand is used to enable (SC register !!XX!! 00h) or disable (SC register |
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| = 00h) the setting of the automatic saving feature for the device attribute data. The |
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| setting is maintained every time the device is turned off and then on. When the |
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| automatic saving feature is enabled, the attribute values are saved before the device |
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| enters the power saving mode. However, if the failure prediction feature is disabled, |
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| the attribute values are not automatically saved. |
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| When the device receives this subcommand, it asserts the BSY bit, enables or |
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| disables the automatic saving feature, then clears the BSY bit. |
X’D3’ |
| SMART Save Attribute Values: |
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| When the device receives this subcommand, it asserts the BSY bit, saves device |
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| attribute value data, then clears the BSY bit. |
X’D8’ |
| SMART Enable Operations: |
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| This subcommand enables the failure prediction feature. The setting is maintained |
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| even when the device is turned off and then on. |
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| When the device receives this subcommand, it asserts the BSY bit, enables the failure |
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| prediction feature, then clears the BSY bit. |
X’D9’ |
| SMART Disable Operations: |
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| This subcommand disables the failure prediction feature. The setting is maintained |
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| even when the device is turned off and then on. |
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| When the device receives this subcommand, it asserts the BSY bit, disables the |
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| failure prediction feature, then clears the BSY bit. |
X’DA’ |
| SMART Return Status: |
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| When the device receives this subcommand, it asserts the BSY bit and saves the |
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| current device attribute values. Then the device compares the device attribute values |
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| with insurance failure threshold values. If there is an attribute value exceeding the |
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| threshold, F4h and 2Ch are loaded into the CL and CH registers. If there are no |
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| attribute values exceeding the thresholds, 4Fh and C2h are loaded into the CL and |
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| CH registers. After the settings for the CL and CH registers have been determined, |
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| 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
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