Cypress CY7C1231H manual Pin Definitions, Name, Description, Power supply for the I/O circuitry

CY7C1231H

Pin Definitions

Name

I/O

Description

A0, A1, A

Input-

Address Inputs used to select one of the 128K address locations. Sampled at the rising edge of

Synchronous

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

BW

[A:B]

Input-

Byte Write Inputs, active LOW. Qualified with

WE

to conduct writes to the SRAM. Sampled on the

Synchronous

rising edge of CLK.

WE

Input-

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

CEN

is active LOW. This

Synchronous

signal must be asserted LOW to initiate a write sequence.

ADV/LD

Input-

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

Synchronous

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

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

CEN.

CLK

is only recognized if CEN is active LOW.

CE

1

Input-

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

Synchronous

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 with

Synchronous

CE1 and CE3 to select/deselect the device.

CE

3

Input-

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

Synchronous

CE1 and CE2 to select/deselect the device.

OE

Input-

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

Asynchronous

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.

CEN

Input-

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

Synchronous

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” condition

Asynchronous

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-

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

Synchronous

the rising edge of CLK. As outputs, they deliver the data contained in the memory location specified

by address during the clock rise of the read cycle. The direction of the pins is controlled by OE and

the internal control logic. When

OE

is asserted LOW, the pins can behave as outputs. When HIGH,

DQs and DQP[A:B] 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.

DQP[A:B]

I/O-

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

Synchronous

sequences, DQP[A:B] is controlled by BWx correspondingly.

Mode

Input

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

Strap Pin

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.

NC

–

No Connects. Not Internally connected to the die. 4M, 9M, 18M, 36M, 72M, 144M, 288M, 576M, and

1G are address expansion pins and are not internally connected to the die.

Document #: 001-00207 Rev. *B Page 3 of 12

[+] Feedback