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T
S
3
2
M
~
1
G
C
F
8
0
T
S
3
2
M
~
1
G
C
F
8
0
T
S
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~
1
G
C
F
8
0
80X CompactFlash Card
This command uses DMA mode to write from 1 to 256 sectors as specified in the Sector Count register. A sector count of
0 requests 256 sectors. The transfer begins at the sector specified in the Sector Number Register. When this command
is issued the CompactFlash Storage Card sets BSY, puts all or part of the sector of data in the buffer. The Card is then
permitted, although not required, to set DRQ, clear BSY. The Card asserts DMAREQ while data is available to be
transferred. The host then writes the (512 * sector-count) bytes of data to the Card using DMA. While DMAREQ is
asserted by the Card, the Host asserts -DMACK while it is ready to transfer data by DMA and asserts -IOWR once for
each 16 bit word to be transferred from the Host.
Interrupts are not generated on every sector, but upon completion of the transfer of the entire number of sectors to be
transferred or upon the occurrence of an unrecoverable error.
At command completion, the Command Block Registers contain the cylinder, head and sector number of the last sector
read. If an error occurs, the read terminates at the sector where the error occurred. The Command Block Registers
contain the cylinder, head, and sector number of the sector where the error occurred. The amount of data transferred is
indeterminate.
When a Write DMA command is received by the Card and 8 bit transfer mode has been enabled by the Set Features
command, the Card shall return the Aborted error.
5.6.27 Write Multiple Command - C5h
Note: This specification requires that CompactFlash Cards support a multiple block count of 1 and permits larger values
to be supported.
This command is similar to the Write Sectors command. The CompactFlash Storage 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.
DRQ qualification of the transfer is required only at the start of the data block, not on each sector.The block count of
sectors to be transferred without intervening interrupts is programmed by the Set Multiple Mode command, which shall 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 = (sector count) modulo (block count).
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 shall be rejected with an aborted command error.
Transcend Information Inc.
69
V 1 . 1
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