5.3 Host Commands
Features Resister | Function |
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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 |
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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
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
1F7H(CM) | 1 | 0 |
| 1 | 1 | 0 | 0 | 0 | 0 |
1F6H(DH) | × | × |
| × | DV | xx |
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1F5H(CH) | Key (C2h) |
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1F4H(CL) | Key (4Fh) |
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1F3H(SN) | xx |
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1F2H(SC) | xx |
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1F1H(FR) | Subcommand |
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