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SanDisk CompactFlash Card OEM Product Manual ATA Command Description
5.1.26 Write DMA Command–CAH, CBH
The Write DMA command in Table 5 33 executes in a similar manner to WRITE SECTOR(S)
except for the following:
• The host initialised the DMA channel prior to issuing the command.
• Data transfers are qualified by DMARQ and are performed by the DMA channel.
• The device issues only one interrupt per command to indicate that data transfer has termi-
nated and status is available.
During the execution of a Write DMA command, the device provides status of the BSY bit or
the DRQ bit until the command is completed.
Table 5-36 Write DMA Command
Bit 7 6 5 4 3 2 1 0
Command (7) CAH or CBH
C/D/H (6) 1 LBA 1 Drive Head (LBA 27-24)
Cyl High (5) Cylinder High (LBA 23-16)
Cyl Low (4) Cylinder Low (LBA 15-8)
Sec Num (3) Sector Number (LBA 7-0)
Sec Cnt (2) Sector Count
Feature (1) X
5.1.27 Write Long Sector–32H, 33H
This command is provided for compatibility purposes and is similar to the Write Sector(s)
command except that it writes 516 bytes instead of 512 bytes. Only single sector Write Long
operations are supported. The transfer consists of 512 bytes of data transferred in word mode
followed by 4 bytes of ECC transferred in byte mode. Because of the unique nature of the
solid-state CompactFlash Memory Card, the four bytes of ECC transferred by the host cannot
be used by it. The card discards these four bytes and writes the sector with valid ECC fields.
This command has the same protocol as the Write Sector(s) command.
Table 5-37 Write Long Sector
Bit 7 6 5 4 3 2 1 0
Command (7) 32H or 33H
C/D/H (6) 1 LBA 1 Drive Head (LBA 27-24)
Cyl High (5) Cylinder High (LBA 23-16)
Cyl Low (4) Cylinder Low (LBA 15-8)
Sec Num (3) Sector Number (LBA 7-0)
Sec Cnt (2) X
Feature (1) X
5.1.28 Write Multiple Command–C5H
This command is similar to the Write Sectors command. The card sets BSY within 400 nsec of
accepting the command. Interrupts are not presented on each sector but on the transfer of a
block that contains the number of sectors defined by Set Multiple. Command execution is
identical to the Write Sectors operation except that the number of sectors defined by the Set
Multiple command is transferred without intervening interrupts.
© 2007 SanDisk Corporation 5-25 Rev. 12.0, 02/07