XM20C64

5

A.C. CHARACTERISTICS (Over the recommended operating conditions unless otherwise specified)

Read Cycle Limits

Limits

Symbol

Parameter

Min.

Max.

Units

Read Cycle Time

55

ns

Chip Enable Access Time

55

ns

Address Access Time

55

ns

Output Enable Access Time

30

ns

CE Low to Output in Low Z

0

ns

OE Low to Output in Low Z

0

ns

CE High to Output in Low Z

0

25

ns

OE High to Output in Low Z

0

25

ns

Output Hold

0

ns

3874 PGM T03

MODE SELECTION

CE

WE

NE

OE

Mode

I/O State

Power

H

X

X

X

Module Not Selected

High Z

Standby

L

H

H

L

Read RAM Active

Data Output

Active

L

L

H

X

Write RAM

Data Input

Active

L

L

L

H

Issue Software Command

Data Input

Active

L

H

H

H

Output Disabled

High Z

Active

L

H

L

L

Hardware Array Recall

High Z

Active

L

H

L

H

No Operation

High Z

Active

L

L

L

L

Not Allowed

High Z

Active

3874 PGM T04.1

Read Cycle Timing Diagram

3874 FHD F05

Note:

measured from the point when

CE or OE return high (whichever occurs first) to the time when the outputs are no longer driven.

tCE

tRC

ADDRESS

CE

OE

tOE

tLZ

tOLZ

tOH

tAA

tHZ

tOHZ

I/O

tOE