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CompactFlash Memory Card Interface Description
Function Code
Standby Mode
Byte Read Access (8 bits)
Byte Write Access (8 bits)
Word Read Access (16 bits)
Word Write Access (16 bits)
Odd Byte Read Only (8 bits)
Odd Byte Write Only (8 bits)
3.7. True IDE Mode I/O Transfer Function
This section contains valuable information on the True IDE Mode I/O Transfer function.
3.7.1. True IDE Mode I/O Function
The CompactFlash Memory Card can be configured in a True IDE Mode of operation. This CompactFlash Card is
configured in this mode only when the -OE input signal is grounded by the host when power is applied to the card.
In this True IDE Mode, the PCMCIA protocol and configuration are disabled and only I/O operations to the Task
File and Data Register are allowed. In this mode, no Memory or Attribute Registers are accessible to the host.
CompactFlash Cards permit 8 bit data accesses if the user issues a Set Feature Command to put the device in 8-bit
Mode.
NOTE: Removing and reinserting the CompactFlash Memory Card while the host computer's power is on will
reconfigure the CompactFlash Card to PC Card ATA mode from the original True IDE Mode. To configure
the CompactFlash Card in True IDE Mode, the 50-pin socket must be power cycled with the CompactFlash
Card inserted and -OE (output enable) grounded by the host.
Table 3-24 defines the function of the operations for the True IDE Mode.
Function Code
Invalid Mode
Standby Mode
Task File Write
Task File Read
Data Register Write
Data Register Read
Control Register Write
Alt Status Read
3-24
Table 3-23. Common Memory Function
-REG
-CE2
-CE1
X
H
H
H
H
L
H
H
L
H
H
L
H
H
L
H
L
L
H
L
L
H
L
H
H
L
H
Table 3-24. IDE Mode I/O Function
-CE2
-CE1
A0
L
L
X
H
H
X
H
L
1-7h
H
L
1-7h
H
L
0
H
L
0
L
H
6h
L
H
6h
®
CompactFlash
Memory Card Product Manual, Rev. 10.0 © 2002 SANDISK CORPORATION
A0
-OE
-WE
X
X
X
L
L
H
H
L
H
L
H
L
H
H
L
X
L
H
X
H
L
X
L
H
X
H
L
-IORD
-IOWR
D15-D8
X
X
X
X
H
L
Do not care
L
H
H
L
Odd-Byte
L
H
Odd-Byte
H
L
Do not care
L
H
D15-D8
D7-D0
High Z
High Z
High Z
Even-Byte
High Z
Odd-Byte
Do not care
Even-Byte
Do not care
Odd-Byte
Odd-Byte
Even-Byte
Odd-Byte
Even-Byte
Odd-Byte
High Z
Odd-Byte
Do not care
D7-D0
High Z
High Z
High Z
High Z
Data In
High Z
Data Out
Even-Byte
In
In
Even-Byte
Out
Out
Control In
High Z
Status Out
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