Fujitsu MHW2040AC, Product Manual

Page: 139 / 278

5.3 Host Commands
(18) READ MULTIPLE (X’C4’)
The READ MULTIPLE Command performs the same as the READ SECTOR(S)
Command except that when the device is ready to transfer data for a block of
sectors, and enters the interrupt pending state only before the data transfer for the
first sector of the block sectors. In the READ MULTIPLE command operation,
the DRQ bit of the Status register is set only at the start of the data block, and is
not set on each sector.
The number of sectors per block is defined by a successful SET MULTIPLE
MODE Command. The SET MULTIPLE MODE command should be executed
prior to the READ MULTIPLE command.
If the number of requested sectors is not divided evenly (having the same number
of sectors [block count]), as many full blocks as possible are transferred, then a
final partial block is transferred. The number of sectors in the partial block to be
transferred is n where n = remainder of (“number of sectors”/”block count”).
If the READ MULTIPLE command is issued before the SET MULTIPLE MODE
command is executed or when the READ MULTIPLE command is disabled, the
device rejects the READ MULTIPLE command with an ABORTED COMMAND
error.
Figure 5.2 shows an example of the execution of the READ MULTIPLE
command.
•
Block count specified by SET MULTIPLE MODE command = 4 (number of
sectors in a block)
•
READ MULTIPLE command specifies;
Number of requested sectors = 9 (Sector Count register = 9)
Figure 5.2 Execution example of READ MULTIPLE command
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