Cypress NoBL CY7C1470V33 Manuale Utente Scaricare il pdf (Pagina 6)

CY7C1470V33

CY7C1472V33

CY7C1474V33

Document #: 38-05289 Rev. *I Page 6 of 29

Pin Definitions

Pin Name I/O Type Pin Description

Input-

Synchronous

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

the CLK.

Input-

Synchronous

Byte Write Select Inputs, active LOW. Qualified with WE to conduct writes to the SRAM.

Sampled on the rising edge of CLK. BW

controls DQ

and DQP

, BW

controls DQ

and DQP

controls DQ

and DQP

, BW

controls DQ

and DQP

, BW

controls DQ

and DQP

, BW

controls DQ

and DQP

, BW

controls DQ

and DQP

, BW

controls DQ

and DQP

Input-

Synchronous

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

signal must be asserted LOW to initiate a write sequence.

ADV/LD Input-

Synchronous

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

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

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.

Input-

Synchronous

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

and CE

to select/deselect the device.

Input-

Synchronous

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

and CE

to select/deselect the device.

Input-

Synchronous

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

and

to select/deselect the device.

Input-

Asynchronous

Output Enable, active LOW. Combined with the synchronous logic 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

and when the device has been deselected.

CEN

Input-

Synchronous

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

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 A

[17:0]

during the previous 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, DQ

–DQ

are placed in a tri-state condition. The outputs are automat-

ically 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

I/O-

Synchronous

Bidirectional Data Parity I/O lines. Functionally, these signals are identical to DQ

. During write

sequences, DQP

is controlled by BW

, DQP

is controlled by BW

, DQP

is controlled by BW

and DQP

is controlled by BW

, DQP

is controlled by BW

, DQP

is controlled by BW

, DQP

is controlled by BW

, DQP

is controlled by BW

MODE Input Strap Pin Mode Input. Selects the burst order of the device. Tied HIGH selects the interleaved burst order.

Pulled LOW selects the linear burst order. MODE should not change states during operation.

When left floating MODE will default HIGH, to an interleaved burst order.

TDO JTAG Serial

Output

Synchronous

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

TDI JTAG Serial Input

Synchronous

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

[+] Feedback

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