Specifications

• The drive issues only one interrupt per command to indicate that data
transfer has ended and drive status is available.
Any error encountered during Write DMA execution results in the termi-
nation of data transfer. The drive issues an interrupt to indicate that data
transfer has terminated and status is available in the Error register. The
error posting is the same as that of the Write Sectors command. If the
no-retry command code (CB
H
) is issued, some or all of the error recovery
procedures normally used with this command may be skipped.
5.4.18 Write Long command
This command (command codes 32
H
and 33
H
) is similar to the Write
Sectors command except that it writes the data and the ECC bytes
directly from the sector buffer; the drive does not generate the ECC bytes
itself. Only single sector Write Long operations are supported.
After transferring a single block of 512-bytes, the drive transfers the ECC
bytes one byte at a time. If the no-retry command code (33
H
) is issued,
some or all of the error recovery procedures normally used with this
command may be skipped.
Also see the Identify Drive and Set Features commands.
5.4.19 Write Multiple command
This command (command code C5
H
) is similar to the Write Sectors
command. Interrupts are not presented on each sector but on the transfer
of a block which contains the number of sectors defined by Set Multiple
Mode command.
The number of sectors per block to be transferred without intervening
interrupts is programmed by the Set Multiple Mode command, which
must be executed prior to the Write Multiple command.
When the Write Multiple command is issued, the Sector Count register
contains the number of sectors (not the number of blocks or the block
count) requested.
If the number of requested sectors is not evenly divisible by the block
count, as many full blocks as possible are transferred, followed by a final,
partial block transfer. The partial block transfer is for
n sectors, where
n = remainder (sector count / block count)
If the Write Multiple command is attempted before the Set Multiple Mode
command has been executed or when Write Multiple commands are
ATA Interface Reference Manual, Rev. C 53