Seagate Medalist ST31082A, Product Manual

Page: 73 / 92

Command Set Chapter 7
Technical Reference Manual Page 61
Set Multiple Mode
Command Number: C6 hex
Description: This command enables the controller to perform Read Multiple
and Write Multiple operations and establishes the block count for these
commands. Prior to command issuance, the Sector Count register should be
loaded with the number of sectors per block. Block counts supported are
multiples of 2 up to the value reported in word 47 of the Identify Device
command data, e.g. 1,2,4,8.
Upon receipt of the command, the controller sets BSY and looks at the Sector
Count register contents. If the register contents are valid and a supported block
count is supplied, that value is loaded for all subsequent Read Multiple and
Write Multiple commands and execution of these commands is enabled. Any
unsupported block count in the register will result in an Aborted Command
Error and any Read Multiple and Write Multiple commands will be disabled.
If the Sector Count register contains 0 when the command is issued, any Read
Multiple and Write Multiple commands will be disabled. Once the
appropriate action has been taken, the controller resets BSY and generates an
interrupt. At power-up the default is for Read Multiple and Write Multiple
to be disabled.
The state of Read Multiple and Write Multiple is maintained through both
hardware and software resets.