SRV01-SRV04
White Electronic Designs
CARD SIGNAL DESCRIPTION
Symbol
Type
Name and Function
A0 - A25
INPUT
ADDRESS INPUTS: A0 through A25 enable direct addressing of up to 64MB of memory on the card. Signal A0 is not
used in word access mode. A25 is the most significant bit. (address pins used are based on card density,see pinout
for highest used address pin)
DQ0 - DQ15
CE1#, CE2#
INPUT/OUTPUT
INPUT
DATA INPUT/OUTPUT: DQ0 THROUGH DQ15 constitute the bi-directional databus. DQ0 - DQ7 constitute the lower
(even) byte and DQ8 - DQ15 the upper (odd) byte. DQ15 is the MSB.
CARD ENABLE 1 AND 2: CE1# enables even byte accesses, CE2# enables odd byte accesses. Multiplexing A0,
CE1# and CE2# allows 8-bit hosts to access all data on DQ0 - DQ7.
OE#
INPUT
OUTPUT ENABLE: Active low signal enabling read data from the memory card.
WRITE ENABLE: Active low signal gating write data to the memory card.
READY/BUSY OUTPUT: Not used for SRAM cards
WE#
INPUT
RDY/BSY#
CD1#, CD2#
OUTPUT
OUTPUT
CARD DETECT 1 and 2: Provide card insertion detection. These signals are connected to ground internally on the
memory card. The host socket interface circuitry shall supply 10K-ohm or larger pull-up resistors on these signal pins.
WP
OUTPUT
N.C.
WRITE PROTECT: Follows hardware Write Protect Switch. When Switch is placed in on position, signal is pulled high
(10K ohm). When switch is off signal is pulled low.
VPP1, VPP2
VCC
PROGRAM/ERASE POWER SUPPLY: Not used for SRAM cards.
CARD POWER SUPPLY: 5.0V for all internal circuitry.
GND
GROUND: for all internal circuitry.
REG#
INPUT
ATTRIBUTE MEMORY SELECT: only used with cards built with optional attribute memory.
RESET: Not used for SRAM cards
RST
INPUT
WAIT#
BVD1, BVD2
OUTPUT
OUTPUT
WAIT: This signal is pulled high internally for compatibility. No wait states are generated.
BATTERY VOLTAGE DETECT: Provides status of Battery voltage.
BVD2 = BVD1 = VOH (battery voltage is guaranteed to retain data)
BVD2 = VOL, BVD1 = Voh (data is valid, battery recharge required)
BVD2 = BVD1 = VOL (data may no longer be valid, battery requires extended recharge)
VS1, VS2
OUTPUT
VOLTAGE SENSE: Notifies the host socket of the card’s VCC requirements. VS1 and VS2 are open to indicate a 5V,
16 bit card has been inserted.
RFU
N.C.
RESERVED FOR FUTURE USE
NO INTERNAL CONNECTION TO CARD: pin may be driven or left floating
SRAM FUNCTIONAL TRUTH TABLE
READ function
Function Mode
Standby Mode
Common Memory
D15-D8
Attribute Memory
D15-D8
CE2# CE1# A0 OE# WE#
REG#
D7-D0
High-Z
REG#
D7-D0
High-Z
H
H
H
L
H
L
X
L
X
L
L
L
L
X
H
H
H
H
X
H
H
H
H
High-Z
X
L
L
L
L
High-Z
Byte Access (8 bits)
High-Z
Even-Byte
Odd-Byte
Even-Byte
High-Z
High-Z
Even-Byte
Not Valid
Even-Byte
High-Z
L
H
X
X
High-Z
High-Z
Word Access (16 bits)
Odd-Byte Only Access
L
Odd-Byte
Odd-Byte
Not Valid
Not Valid
L
H
WRITE function
Standby Mode
H
H
H
H
L
L
X
L
X
H
H
X
L
L
X
H
H
X
X
X
X
X
L
L
X
X
X
X
Even-Byte
X
Byte Access (8 bits)
Even-Byte
Odd-Byte
H
February 2007
Rev. 2
5
White Electronic Designs Corporation • (602) 437-1520 • www.whiteedc.com
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