CompactFlash Memory Card Product Manual
SanDisk CompactFlash Memory Card Product Manual © 1998 SANDISK CORPORATION
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Changed
Indicates that one or both of the Pin Replacement register CRdy, or CWProt bits are set to one (1).
When the Changed bit is set, -STSCHG Pin 46 is held low if the SigChg bit is a One (1) and the
CompactFlash Memory Card is configured for the I/O interface.
SigChg
This bit is set and reset by the host to enable and disable a state-change “signal” from the Status
Register, the Changed bit control pin 46 the Changed Status signal. If no state change signal is
desired, this bit should be set to zero (0) and pin 46 (-STSCHG) signal will be held high while the
CompactFlash Memory Card is configured for I/O.
I O i s 8
The host sets this bit to a one (1) if the CompactFlash Memory Card is to be configured in an 8 bit
I/O mode. The CompactFlash Card is always configured for both 8- and 16-bit I/O, so this bit is
ignored.
PwrDwn
This bit indicates whether the host requests the CompactFlash Memory Card to be in the power
saving or active mode. When the bit is one (1), the CompactFlash Card enters a power down mode.
When zero (0), the host is requesting the CompactFlash Card to enter the active mode. The
PCMCIA Rdy/-Bsy value becomes BUSY when this bit is changed. Rdy/-Bsy will not become Ready
until the power state requested has been entered. The CompactFlash Card automatically powers
down when it is idle and powers back up when it receives a command.
I n t
This bit represents the internal state of the interrupt request. This value is available whether or not
I/O interface has been configured. This signal remains true until the condition which caused the
interrupt request has been serviced. If interrupts are disabled by the -IEN bit in the Device Control
Register, this bit is a zero (0).
4.4.4
Pin Replacement Register (Address 204h
in Attribute Memory)
Operation
D7
D6
D5
D4
D3
D2
D1
D0
Read
0
0
CRdy/-Bsy
CWProt
1
1
RRdy/-Bsy
RWProt
Write
0
0
CRdy/-Bsy
CWProt
0
0
MRdy/-Bsy
MWProt
CRdy/-Bsy
This bit is set to one (1) when the bit RRdy/-Bsy changes state. This bit can also be written by the
host.
CWProt
This bit is set to one (1) when the RWprot changes state. This bit may also be written by the host.
RRdy/-Bsy
This bit is used to determine the internal state of the Rdy/-Bsy signal. This bit may be used to
determine the state of the Ready/-Busy as this pin has been reallocated for use as Interrupt
Request on an I/O card. When written, this bit acts as a mask for writing the corresponding bit
CRdy/-Bsy.
RWProt
This bit is always zero (0) since the CompactFlash Memory Card does not have a Write Protect
switch. When written, this bit acts as a mask for writing the corresponding bit CWProt.
M R d y / - B s y
This bit acts as a mask for writing the corresponding bit CRdy/-Bsy.
MWProt
This bit when written acts as a mask for writing the corresponding bit CWProt.
