SMCXXXAF Datasheet, PDF (36/82 Pages) Numonyx B.V – 32 Mbyte, 64 Mbyte, 128 Mbyte, 256 Mbyte and 512 Mbyte 3.3 V / 5 V supply CompactFlash™ card

Card configuration
SMCxxxAF
6.6
I/O transfer function
The I/O transfer to or from the card can be either 8 or 16 bits. When a 16 bit accessible port
is addressed, the –IOIS16 signal is asserted by the card, otherwise it is de-asserted. When
a 16 bit transfer is attempted, and the –IOIS16 signal is not asserted, the system must
generate a pair of 8 bit references to access the word’s even and odd bytes. The card
permits both 8 and 16 bit accesses to all of its I/O addresses, so –IOIS16 is asserted for all
addresses (see Table 32).
Table 32. I/O function
Function code
–REG
Standby mode
X
Byte input access
L
(8 bits)
L
Byte output access
L
(8 bits)
L
Word input access
L
(16 bits)
Word output access
L
(16 bits)
I/O Read Inhibit
H
I/O Write inhibit
H
High byte input only
L
(8 bits)
High byte output only
L
(8 bits)
–CE2
H
H
H
H
H
L
L
X
X
L
L
–CE1 A0
H
X
L
L
L
H
L
L
L
H
L
L
L
L
X
X
X
X
H
X
H
X
–IORD
X
L
L
H
H
L
H
L
H
L
H
–IOWR
X
H
H
L
L
H
L
H
L
H
L
D15 to D8
High Z
High Z
High Z
Don’t care
Don’t care
Odd byte
Odd byte
Don’t care
High Z
Odd byte
Odd byte
D7 to D0
High Z
Even byte
Odd byte
Even byte
Odd byte
Even byte
Even byte
Don’t care
High Z
High Z
Don’t care
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