Cypress CY7C1357C manual Pin Definitions, Name Description, Power supply for the I/O circuitry

CY7C1355C

CY7C1357C

Pin Definitions

Name

I/O

Description

A0, A1, A

Input-

Address Inputs used to select one of the address locations. Sampled at the rising edge

Synchronous

of the CLK. A[1:0] are fed to the two-bit burst counter.

A,

B

Input-

Byte Write Inputs, active LOW. Qualified with

to conduct Writes to the SRAM. Sampled

BW

BW

WE

BWC, BWD

Synchronous

on the rising edge of CLK.

Input-

Write Enable Input, active LOW. Sampled on the rising edge of CLK if

is active LOW.

WE

CEN

Synchronous

This signal must be asserted LOW to initiate a write sequence.

Input-

Advance/Load Input. Used to advance the on-chip address counter or load a new address.

ADV/LD

Synchronous

When HIGH (and CEN is asserted LOW) the internal burst counter is advanced. When LOW,

a new address can be loaded into the device for an access. After being deselected, ADV/LD

should be driven LOW in order to load a new address.

CLK

Input-

Clock Input. Used to capture all synchronous inputs to the device. CLK is qualified with

Clock

CEN. CLK is only recognized if CEN is active LOW.

1

Input-

Chip Enable 1 Input, active LOW. Sampled on the rising edge of CLK. Used in conjunction

CE

Synchronous

with CE2, and CE3 to select/deselect the device.

CE2

Input-

Chip Enable 2 Input, active HIGH. Sampled on the rising edge of CLK. Used in conjunction

Synchronous

with CE1 and CE3 to select/deselect the device.

3

Input-

Chip Enable 3 Input, active LOW. Sampled on the rising edge of CLK. Used in conjunction

CE

Synchronous

with CE1 and CE2 to select/deselect the device.

Input-

Output Enable, asynchronous input, active LOW. Combined with the synchronous logic

OE

Asynchronous

block inside the device to control the direction of the I/O pins. When LOW, the I/O pins are

allowed to behave as outputs. When deasserted HIGH, I/O pins are tri-stated, and act as

input data pins. OE is masked during the data portion of a write sequence, during the first

clock when emerging from a deselected state, when the device has been deselected.

Input-

Clock Enable Input, active LOW. When asserted LOW the Clock signal is recognized by

CEN

Synchronous

the SRAM. When deasserted HIGH the Clock signal is masked. Since deasserting CEN

does not deselect the device, CEN can be used to extend the previous cycle when required.

ZZ

Input-

ZZ “Sleep” Input. This active HIGH input places the device in a non-time critical “sleep”

Asynchronous

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

I/O-

Bidirectional Data I/O lines. As inputs, they feed into an on-chip data register that is

Synchronous

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.The

outputs are automatically tri-stated during the data portion of a Write sequence, during the

first clock when emerging from a deselected state, and when the device is deselected,

regardless of the state of OE.

DQPX

I/O-

Bidirectional Data Parity I/O Lines. Functionally, these signals are identical to DQs. During

Synchronous

Write sequences, DQPX is controlled by BWX correspondingly.

MODE

Input Strap Pin

Mode Input. Selects the burst order of the device. When tied to Gnd selects linear burst

sequence. When tied to VDD or left floating selects interleaved burst sequence.

VDD

Power Supply

Power supply inputs to the core of the device.

VDDQ

I/O Power

Power supply for the I/O circuitry.

Supply

VSS

Ground

Ground for the device.

TDO

JTAG serial output

Serial data-out to the JTAG circuit. Delivers data on the negative edge of TCK. If the JTAG

Synchronous

feature is not being utilized, this pin should be left unconnected. This pin is not available on

TQFP packages.

TDI

JTAG serial input

Serial data-In to the JTAG circuit. Sampled on the rising edge of TCK. If the JTAG feature

Synchronous

is not being utilized, this pin can be left floating or connected to VDD through a pull up resistor.

This pin is not available on TQFP packages.

Document #: 38-05539 Rev. *E

Page 7 of 28

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