CY7C1484V25
CY7C1485V25
Document #: 38-05286 Rev. *H
Page 5 of 26
Pin Definitions
Pin Name
IO
Description
A0, A1, A
Input-
Synchronous
Address Inputs used to select one of the address locations. Sampled at the rising edge
of the CLK if ADSP or ADSC is active LOW, and CE1, CE2, and CE3 are sampled active. A1:
A0 are fed to the two-bit counter.
BWA,BWB
BWC,BWD
Input-
Synchronous
Byte Write Select Inputs, active LOW. Qualified with BWE to conduct byte writes to the
SRAM. Sampled on the rising edge of CLK.
GW
Input-
Synchronous
Global Write Enable Input, active LOW. When asserted LOW on the rising edge of CLK, a
global write is conducted (ALL bytes are written, regardless of the values on BWX and BWE).
BWE
Input-
Synchronous
Byte Write Enable Input, active LOW. Sampled on the rising edge of CLK. This signal must
be asserted LOW to conduct a byte write.
CLK
Input-
Clock
Clock Input. Used to capture all synchronous inputs to the device. Also used to increment
the burst counter when ADV is asserted LOW during a burst operation.
CE1
Input-
Synchronous
Chip Enable 1 Input, active LOW. Sampled on the rising edge of CLK. Used in conjunction
with CE2 and CE3 to select or deselect the device. ADSP is ignored if CE1 is HIGH. CE1 is
sampled only when a new external address is loaded.
CE2
Input-
Synchronous
Chip Enable 2 Input, active HIGH. Sampled on the rising edge of CLK. Used in conjunction
with CE1 and CE3 to select or deselect the device. CE2 is sampled only when a new external
address is loaded.
CE3
Input-
Synchronous
Chip Enable 3 Input, active LOW. Sampled on the rising edge of CLK. Used in conjunction
with CE1 and CE2 to select or deselect the device. CE3 is sampled only when a new external
address is loaded.
OE
Input-
Asynchronous
Output Enable, asynchronous input, active LOW. Controls the direction of the IO pins.
When LOW, the IO pins behave as outputs. When deasserted HIGH, DQ pins are tri-stated,
and act as input data pins. OE is masked during the first clock of a read cycle when emerging
from a deselected state.
ADV
Input-
Synchronous
Advance Input signal, sampled on the rising edge of CLK, active LOW. When asserted,
it automatically increments the address in a burst cycle.
ADSP
Input-
Synchronous
Address Strobe from Processor, sampled on the rising edge of CLK, active LOW. When
asserted LOW, addresses presented to the device are captured in the address registers. A1:
A0 are also loaded into the burst counter. When ADSP and ADSC are both asserted, only
ADSP is recognized. ASDP is ignored when CE1 is deasserted HIGH.
ADSC
Input-
Synchronous
Address Strobe from Controller, sampled on the rising edge of CLK, active LOW. When
asserted LOW, addresses presented to the device are captured in the address registers. A1:
A0 are also loaded into the burst counter. When ADSP and ADSC are both asserted, only
ADSP is recognized.
ZZ
Input-
Asynchronous
ZZ “sleep” Input, active HIGH. When asserted HIGH, places the device in a non-time-critical
“sleep” condition with data integrity preserved. For normal operation, this pin has to be LOW
or left floating. ZZ pin has an internal pull down.
DQs, DQPs
IO-
Synchronous
Bidirectional Data IO lines. As inputs, they feed into an on-chip data register that is triggered
by the rising edge of CLK. As outputs, they deliver the data contained in the memory location
specified by the addresses presented during the previous clock rise of the read cycle. The
direction of the pins is controlled by OE. When OE is asserted LOW, the pins behave as
outputs. When HIGH, DQs and DQPX are placed in a tri-state condition.
VDD
Power Supply
Power supply inputs to the core of the device.
VSS
Ground
Ground for the core of the device.
VSSQ[2]
IO Ground
Ground for the IO circuitry.
VDDQ
IO Power Supply Power supply for the IO circuitry.
Note
2. Applicable for TQFP package. For BGA package VSS serves as ground for the core and the IO circuitry.
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