Cypress CY7C1338G - Manual (Page 4)

CY7C1338G
Document #: 38-05521 Rev. *D Page 4 of 17
Functional Overview
All synchronous inputs pass through input registers controlled
by the rising edge of the clock. Maximum access delay from
the clock rise (t
C0
) is 6.5 ns (133-MHz device).
The CY7C1338G supports secondary cache in systems
utilizing either a linear or interleaved burst sequence. The
interleaved burst order supports Pentium and i486
™
processors. The linear burst sequence is suited for processors
that utilize a linear burst sequence. The burst order is
user-selectable, and is determined by sampling the MODE
input. Accesses can be initiated with either the Processor
Address Strobe (ADSP) or the Controller Address Strobe
(ADSC). Address advancement through the burst sequence is
controlled by the ADV input. A two-bit on-chip wraparound
burst counter captures the first address in a burst sequence
and automatically increments the address for the rest of the
burst access.
Byte write operations are qualified with the Byte Write Enable
(BWE) and Byte Write Select (BW
[A:D]
) inputs. A Global Write
Enable (GW) overrides all byte write inputs and writes data to
all four bytes. All writes are simplified with on-chip
synchronous self-timed write circuitry.
Three synchronous Chip Selects (CE
1
, CE
2
, CE
3
) and an
asynchronous Output Enable (OE) provide for easy bank
selection and output tri-state control. ADSP is ignored if CE
1
is HIGH.
Single Read Accesses
A single read access is initiated when the following conditions
are satisfied at clock rise: (1) CE
1
, CE
2
, and CE
3
are all
asserted active, and (2) ADSP or ADSC is asserted LOW (if
the access is initiated by ADSC, the write inputs must be
deasserted during this first cycle). The address presented to
the address inputs is latched into the address register and the
burst counter/control logic and presented to the memory core.
If the OE input is asserted LOW, the requested data will be
available at the data outputs a maximum to t
CDV
after clock
rise. ADSP is ignored if CE
1
is HIGH.
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. A
[1:0]
are
also loaded into the burst counter. When ADSP and ADSC are both asserted, only ADSP is recog-
nized. ASDP is ignored when CE
1
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. A
[1:0]
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. During normal operation, this pin has to be low or left floating.
ZZ pin has an internal pull-down.
DQs I/O-
Synchronous
Bidirectional Data I/O 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
are placed in a tri-state condition.
V
DD
Power
Supply
Power supply inputs to the core of the device.
V
SS
Ground Ground for the core of the device.
V
DDQ
I/O Power
Supply
Power supply for the I/O circuitry.
V
SSQ
I/O Ground Ground for the I/O circuitry.
MODE Input-
Static
Selects Burst Order. When tied to GND selects linear burst sequence. When tied to V
DD
or left
floating selects interleaved burst sequence. This is a strap pin and should remain static during device
operation. Mode Pin has an internal pull-up.
NC No Connects. Not Internally connected to the die.
NC/9M,
NC/18M
NC/36M
NC/72M,
NC/144M,
NC/288M,
NC/576M,
NC/1G – No Connects. Not internally connected to the die. NC/9M,NC/18M,NC/36M,NC/72M, NC/144M,
NC/288M, NC/576M and NC/1G are address expansion pins that are not internally connected to
the die.
Pin Definitions (continued)
Name I/O Description