SanDisk CompactFlash Card OEM Product Manual  Interface Description 
Table 3-4  Signal Description 
Signal Name  Dir.  Pin  Description 
-DMACK 
(True IDE Mode) 
This signal is used by the host in response to 
DMARQ to initiate DMA transfers. 
NOTE: This signal may be negated by the host 
to suspend the DMS transfer in process. For 
Multiword DMA transfers, the device may 
negate DMARQ with the t
L 
specified time once 
the DMACK- is asserted and reasserted again 
at a later time to resume DMA operation. 
Alternatively, if the device is able to continue 
the data transfer, the device may leave 
DMARQ asserted and wait for the host to 
reassert DMACK-. 
RESET 
(PC Card Memory Mode) 
(PC Card I/O Mode) 
-RESET 
(True IDE Mode) 
I  41  When the pin is high, this signal resets the 
card. The card is reset only at power-up if this 
pin is left high or open from power-up. The card 
is also reset when the Soft Reset bit in the Card 
Configuration Option Register is set. 
In the True IDE Mode this input pin is the active 
low hardware reset from the host. 
V
CC 
(PC Card Memory Mode) 
(PC Card I/O Mode
) 
(True IDE Mode) 
-- 13, 38  +5V, +3.3V power. 
-VS1 
-VS2 
(PC Card Memory Mode) 
(PC Card I/O Mode
) 
(True IDE Mode) 
O  33, 40  Voltage Sense Signals. -VS1 is grounded so 
that the CompactFlash Card CIS can be read at 
3.3 volts and  VS2 is open and reserved by 
PCMCIA for a secondary voltage. 
-WAIT 
(PC Card Memory Mode) 
-WAIT 
(PC Card I/O Mode) 
IORDY 
(True IDE Mode) 
O  42  SanDisk CompactFlash Memory cards do not 
assert the -WAIT signal. 
SanDisk CompactFlash Memory cards do not 
assert the -WAIT signal. 
SanDisk CompactFlash Memory cards, except 
when in UDMA modes, do not assert an IORDY 
signal. 
-WE 
(PC Card Memory Mode) 
-WE 
(PC Card I/O Mode) 
-WE 
(True IDE Mode) 
I  36  This is a signal driven by the host and used for 
strobing memory write data to the registers of 
the card when it is configured in the Memory 
Interface Mode. It is also used for writing the 
configuration registers. 
In PC Card I/O Mode, this signal is used for 
writing the configuration registers. 
In True IDE Mode this input signal is not used 
and should be connected to VCC by the host. 
WP 
(PC Card Memory Mode) 
O  24  Memory Mode–The CompactFlash Card does 
not have a write-protect switch. This signal is 
held low after the completion of the reset 
initialization sequence. 
© 2007 SanDisk Corporation  3-7  Rev. 12.0, 02/07