SDP3B FlashDisk Product Manual
SanDisk SDP3B FlashDisk Product Manual © 1998 SANDISK CORPORATION
77
The block count of sectors 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 sector/block, 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 = sector count (modulo sector/block).
If the Write Multiple command is attempted
before the Set Multiple Mode command has been
executed or when Write Multiple commands are
disabled, the Write Multiple operation will be
rejected with an aborted command error.
Errors encountered during Write
Multiple
commands are posted after the attempted writes
of the block or partial block transferred. The
Write command ends with the sector in error, even
if it is in the middle of a block. Subsequent blocks
are not transferred in the event of an error.
Interrupts are generated when DRQ is set at the
beginning of each block or partial block.
The Command Block Registers contain the
cylinder, head and sector number of the sector
where the error occurred and the Sector Count
Register contains the residual number of sectors
that need to be transferred for successful
completion of the command e.g. each block has 4
sectors, a request for 8 sectors is issued and an error
occurs on the third sector. The Sector Count
Register contains 6 and the address is that of the
third sector.
6.1.27
Write Multiple without Erase - CDH
Bit ->
7
6
5
4
3
2
1
0
Command (7)
CDH
C / D / H ( 6 )
X
LBA
X
Drive
Head
Cyl High (5)
Cylinder High
Cyl Low (4)
Cylinder Low
Sec Num (3)
Sector Number
Sec Cnt (2)
Sector Count
Feature (1)
X
This command is similar to the Write Multiple
command with the exception that an implied
erase before write operation is not performed. The
sectors should be pre-erased with the Erase
Sector(s) command before this command is issued.
Refer to section 1.7.5 Using the Erase Sector and
Write without Erase Commands
and to section
6.1.29 Write Sector(s) Without Erase - 38H for an
expanded definition of the Write Sector(s)
without Erase command.
