Subcommand code 42h allows the host to enable the Automatic Acoustic Management feature set. To enable the Automatic Acoustic Management feature set, the host writes the Sector Count register with the requested automatic acoustic management level and executes a SET FEATURES command with subcommand code 42h. The acoustic management level is selected on a scale from 01h to FEh. Following table shows the acoustic management level values.
Enabling or disabling of the Automatic Acoustic Management feature set, and the current automatic acoustic management level setting will be preserved by the device across all forms of reset, i.e., power on, hardware, and software resets.
Automatic management levels
Level | Sector Count value |
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Reserved | FFh |
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Maximum performance | C0h - FEh |
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Minimum acoustic emanation level | 80h - BFh |
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Retired | 01h - 7Fh |
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Vendor Specific (Maximum performance) | 00h |
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Subcommand code C2h disables the Automatic Acoustic Management feature set. Devices that implement SET FEATURES subcommand 42h are not required to implement subcommand C2h. If device successfully completes execution of this subcommand, then the acoustic behavior of the device shall be
(15)SET MULTIPLE MODE (X'C6')
This command enables the device to perform the READ MULTIPLE and WRITE MULTIPLE commands. The block count (number of sectors in a block) for these commands are also specified by the SET MULTIPLE MODE command.
The number of sectors per block is written into the Sector Count register. The IDD supports 2, 4, 8 and 16 (sectors) as the block counts.
Upon receipt of this command, the device sets the BSY bit of the Status register and checks the contents of the Sector Count register. If the contents of the Sector Count register is valid and is a supported block count, the value is stored for all subsequent READ MULTIPLE and WRITE MULTIPLE commands. Execution of these commands is then enabled. If the value of the Sector Count register is not a supported block count, an ABORTED COMMAND error is posted and the READ MULTIPLE and WRITE MULTIPLE commands are disabled.
If the contents of the Sector Count register is 0 when the SET MULTIPLE MODE command is issued, the READ MULTIPLE and WRITE MULTIPLE commands are disabled.
When the SET MULTIPLE MODE command operation is completed, the device clears the BSY bit and generates an interrupt.
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