Cypress Semiconductor CY7C1360C Specification Sheet Download Page 8

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CY7C1360C
CY7C1362C

Document #: 38-05540 Rev. *H

Page 8 of 31

Functional Overview

All synchronous inputs pass through input registers controlled
by the rising edge of the clock. All data outputs pass through
output registers controlled by the rising edge of the clock.
Maximum access delay from the clock rise (t

) is 2.8 ns

(250-MHz device).

The CY7C1360C/CY7C1362C 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

) 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

, CE

[2]

) and an

asynchronous Output Enable (OE) provide for easy bank
selection and output tri-state control. ADSP is ignored if CE

is HIGH.

Single Read Accesses

This access is initiated when the following conditions are
satisfied at clock rise: (1) ADSP or ADSC is asserted LOW, (2)
CE

, CE

[2]

are all asserted active, and (3) the Write

signals (GW, BWE) are all deasserted HIGH. ADSP is ignored
if CE

is HIGH. The address presented to the address inputs

(A) is stored into the address advancement logic and the
address register while being presented to the memory array.
The corresponding data is allowed to propagate to the input of
the output registers. At the rising edge of the next clock the
data is allowed to propagate through the output register and
onto the data bus within 2.8 ns (250-MHz device) if OE is
active LOW. The only exception occurs when the SRAM is
emerging from a deselected state to a selected state, its
outputs are always tri-stated during the first cycle of the

access. After the first cycle of the access, the outputs are
controlled by the OE signal. Consecutive single Read cycles
are supported. Once the SRAM is deselected at clock rise by
the chip select and either ADSP or ADSC signals, its output
will tri-state immediately.

Single Write Accesses Initiated by ADSP

This access is initiated when both of the following conditions
are satisfied at clock rise: (1) ADSP is asserted LOW, and
(2) CE

, CE

[2]

are all asserted active. The address

presented to A is loaded into the address register and the
address advancement logic while being delivered to the
memory array. The Write signals (GW, BWE, and BW

) and

ADV inputs are ignored during this first cycle.

ADSP-triggered Write accesses require two clock cycles to
complete. If GW is asserted LOW on the second clock rise, the
data presented to the DQs inputs is written into the corre-
sponding address location in the memory array. If GW is HIGH,
then the Write operation is controlled by BWE and BW

signals. The CY7C1360C/CY7C1362C provides Byte Write
capability that is described in the Write Cycle Descriptions
table. Asserting the Byte Write Enable input (BWE) with the
selected Byte Write (BW

) input, will selectively write to only

the desired bytes. Bytes not selected during a Byte Write
operation will remain unaltered. A synchronous self-timed
Write mechanism has been provided to simplify the Write
operations.

Because the CY7C1360C/CY7C1362C is a common I/O
device, the Output Enable (OE) must be deasserted HIGH
before presenting data to the DQs inputs. Doing so will tri-state
the output drivers. As a safety precaution, DQs are automati-
cally tri-stated whenever a Write cycle is detected, regardless
of the state of OE.

Single Write Accesses Initiated by ADSC

ADSC Write accesses are initiated when the following condi-
tions are satisfied: (1) ADSC is asserted LOW, (2) ADSP is
deasserted HIGH, (3) CE

, CE

[2]

are all asserted active,

and (4) the appropriate combination of the Write inputs (GW,
BWE, and BW

) are asserted active to conduct a Write to the

desired byte(s). ADSC-triggered Write accesses require a
single clock cycle to complete. The address presented to A is
loaded into the address register and the address
advancement logic while being delivered to the memory array.
The ADV input is ignored during this cycle. If a global Write is

TDI

JTAG serial input

Synchronous

Serial data-In to the JTAG circuit

. Sampled on the rising edge of TCK. If the JTAG feature is

not being utilized, this pin can be disconnected or connected to V

. This pin is not available

on TQFP packages.

TMS

JTAG serial input

Synchronous

Serial data-In to the JTAG circuit