T
T
T
S
S
S
8
8
8
G
G
G
~
~
~
1
1
1
6
6
6
G
G
G
C
C
C
F
F
F
6
6
6
0
0
0
0
0
0
600X CompactFlash Card
Transcend Information Inc.
V1.0
44
I/O Transfer Function
The I/O transfer to or from the CompactFlash Storage can be either 8 or 16 bits. When a 16 bit accessible port
is addressed, the signal -IOIS16 is asserted by the CompactFlash Storage. Otherwise, the -IOIS16 signal is
de-asserted. When a 16 bit transfer is attempted, and the -IOIS16 signal is not asserted by the CompactFlash
Storage, the system shall generate a pair of 8 bit references to access the word‘s even byte and odd byte. The
CompactFlash Storage Card permits both 8 and 16 bit accesses to all of its I/O addresses, so -IOIS16 is
asserted for all addresses to which the CompactFlash Storage responds. The CompactFlash Storage Card
may request the host to extend the length of an input cycle until data is ready by asserting the -WAIT signal at
the start of the cycle.
Function Code
DMA
CMD
-REG
-CE2
-CE1
A0
-HIOE
-HIOW
D15-D8
D7-D0
Standby Mode
No
X
H
H
X
X
X
High Z
High Z
UDMA Write
Write
H
H
H
X
X
X
Odd Byte
Even Byte
UDMA Read
Read
H
H
H
X
X
X
Odd Byte
Even Byte
Byte Input Access (8 bits)
X
L
L
H
H
L
L
L
H
L
L
H
H
High Z
High Z
Even-Byte
Odd-Byte
Byte Output Access (8 bits)
X
L
L
H
H
L
L
L
H
H
H
L
L
Don’t Care
Don’t Care
Even-Byte
Odd-Byte
Word Input Access (16 bits)
X
L
L
L
L
L
H
Odd-Byte
Even-Byte
Word Output Access (16 bits)
X
L
L
L
L
H
L
Odd-Byte
Even-Byte
I/O Read Inhibit
X
H
X
X
X
L
H
Don’t Care
Don’t Care
I/O Write Inhibit
X
H
X
X
X
H
L
High Z
High Z
High Byte Input Only (8 bits)
X
L
L
H
X
L
H
Odd-Byte
High Z
High Byte Output Only (8 bits)
X
L
L
H
X
H
L
Odd-Byte
Don’t Care
Table: PCMCIA Mode I/O Function
