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T
T
T
S
S
S
3
3
3
2
2
2
M
M
M
~
~
~
1
1
1
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80X CompactFlash Card
Transcend Information Inc.
65
Features 01h and 81h are used to enable and clear 8 bit data transfer modes in True IDE Mode. If the 01h feature
command is issued all data transfers shall occur on the low order D[7:0] data bus and the -IOIS16 signal shall not be
asserted for data register accesses. The host shall not enable this feature for DMA transfers.
Features 02h and 82h allow the host to enable or disable write cache in CompactFlash Storage Cards that implement
write cache. When the subcommand disable write cache is issued, the CompactFlash Storage Card shall initiate the
sequence to flush cache to non-volatile memory before command completion.
Feature 03h allows the host to select the PIO or Multiword DMA transfer mode by specifying a value in the Sector
Count register. The upper 5 bits define the type of transfer and the low order 3 bits encode the mode value. One PIO
mode shall be selected at all times. For Cards which support DMA, one Multiword DMA mode shall be selected at all
times. The host may change the selected modes by the Set Features command.
Mode Bits(7:3) Bits(2:0)
PIO default mode 00000b 000b
PIO default mode, disable IORDY
00000b 001b
PIO flow control transfer mode 00001b Mode
Reserved 00010b N/A
Multiword DMA mode 00100b Mode
Reserved 01000b N/A
Reserved 10000b N/A
Mode = transfer mode number
A CompactFlash Storage Card reporting support for Multiword DMA modes shall support all Multiword DMA modes below
the highest mode supported. For example, if Multiword DMA mode 2 support is reported, then modes 1 and 0 shall also
be supported.
5.6.19 Set Multiple Mode - C6h
This command enables the CompactFlash Storage Card to perform Read and Write Multiple operations and establishes
the block count for these commands. The Sector Count Register is loaded with the number of sectors per block. Upon
receipt of the command, the CompactFlash Storage Card sets BSY to 1 and checks the Sector Count Register.
If the Sector Count Register contains a valid value and the block count is supported, the value is loaded and execution is
enabled for all subsequent Read Multiple and Write Multiple commands. If the block count is not supported, an Aborted
Command error is posted and the Read Multiple and Write Multiple commands are disabled. If the Sector Count Register
contains 0 when the command is issued, Read and Write Multiple commands are disabled. At power on, or after a
hardware or (unless disabled by a Set Feature command) software reset, the default mode is Read and Write Multiple
disabled.