12/23/04, v 2.6

Alliance Semiconductor

7 of 19

AS7C331MPFS18A

®

1 X = don’t care, L = low, H = high

CE1

CE2

2 For WRITE, L means any one or more byte write enable signals (BWa and BWb) and BWE are LOW or GWE is LOW. WRITE = HIGH for all BWx,

BWE, GWE HIGH. See "Write enable truth table (per byte)," on page 6 for more information.

OE

Address accessed

CLK

Operation

DQ

HXXX

L

X

X

X

NA

L to H

Deselect

Hi

−Z

L

L

X

L

X

X

X

X

NA

L to H

Deselect

Hi

−Z

L

L

X

H

L

X

X

X

NA

L to H

Deselect

Hi

−Z

L

X

H

L

X

X

X

X

NA

L to H

Deselect

Hi

−Z

L

X

H

H

L

X

X

X

NA

L to H

Deselect

Hi

−Z

L

H

L

L

X

X

X

L

External

L to H

Begin read

Q

L

H

L

L

X

X

X

H

External

L to H

Begin read

Hi

−Z

L

H

L

H

L

X

H

L

External

L to H

Begin read

Q

L

H

L

H

L

X

H

H

External

L to H

Begin read

Hi

−Z

XXXHH

L

H

L

Next

L to H

Continue read

Q

XXXHH

L

H

H

Next

L to H

Continue read

Hi

−Z

XXXHH

H

H

L

Current

L to H

Suspend read

Q

XXXHH

H

H

H

Current

L to H

Suspend read

Hi

−Z

HXXXH

L

H

L

Next

L to H

Continue read

Q

HXXXH

L

H

H

Next

L to H

Continue read

Hi

−Z

HXXXH

H

H

L

Current

L to H

Suspend read

Q

HXXXH

H

H

H

Current

L to H

Suspend read

Hi

−Z

L

H

L

H

L

X

L

X

External

L to H

Begin write

3

For write operation following a READ,

4 ZZ pin is always Low.

XXXHH

L

L

X

Next

L to H

Continue write

D

HXXXH

L

L

X

Next

L to H

Continue write

D

XXXHH

H

L

X

Current

L to H

Suspend write

D

HXXXH

H

L

X

Current

L to H

Suspend write

D