Datasheet

T
T
T
S
S
S
4
4
4
G
G
G
~
~
~
3
3
3
2
2
2
G
G
G
C
C
C
F
F
F
1
1
1
5
5
5
0
0
0
150X CompactFlash Card
Transcend Information Inc.
V1.0
42
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 -IORD -IOWR 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