Datasheet

T
T
T
r
r
r
a
a
a
n
n
n
s
s
s
c
c
c
e
e
e
n
n
n
d
d
d
I
I
I
n
n
n
d
d
d
u
u
u
s
s
s
t
t
t
r
r
r
i
i
i
a
a
a
l
l
l
C
C
C
F
F
F
C
C
C
a
a
a
r
r
r
d
d
d
(
(
(
1
1
1
2
2
2
8
8
8
M
M
M
B
B
B
~
~
~
8
8
8
G
G
G
B
B
B
)
)
)
Transcend Information Inc.
39
I/O Transfer Function
The I/O transfer to or from the CompactFlash Storage or CF+ Card can be either 8 or 16 bits. When a 16 bit
accessible port is addressed, the signal -IOIS16 is asserted by the CompactFlash Storage or CF+ Card.
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 or CF+ Card, 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. CF+ cards may or may not allow 16 bit register accesses and thus shall assert -IOIS16 as
required. The CompactFlash Storage and CF+ 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.
Table : PCMCIA Mode I/O Function