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White Electronic Designs Corporation • (602) 437-1520 • www.wedc.com

White Electronic Designs

WED9LAPC2B16P8BC

November 2001

Rev. 1

White Electronic Designs Corp. reserves the right to change products or specifications without notice.

SDRAM CURRENT STATE TRUTH TABLE (continued)

Current State

Command

Action

Notes

BRAS or

PRAS

BCAS or

PCAS

BWE or

PWE

BADDR12,

BADDR13

or PBS

BADDR or

PADDR

Description

Refreshing

L

L

L

OP Code

Mode Register Set

ILLEGAL

L

L

H

X

X

Auto or Self Refresh

ILLEGAL

L

H

L

X

X

Precharge

ILLEGAL

L

H

H

BA

Row Address

Bank Activate

ILLEGAL

H

L

L

BA

Column

Write

ILLEGAL

H

L

H

BA

Column

Read

ILLEGAL

H

H

L

X

X

Burst Termination

H

H

H

X

X

No Operation

Mode Register

Accessing

L

L

L

OP Code

Mode Register Set

ILLEGAL

L

L

H

X

X

Auto or Self Refresh

ILLEGAL

L

H

L

X

X

Precharge

ILLEGAL

L

H

H

BA

Row Address

Bank Activate

ILLEGAL

H

L

L

BA

Column

Write

ILLEGAL

H

L

H

BA

Column

Read

ILLEGAL

H

H

L

X

X

Burst Termination

ILLEGAL

H

H

H

X

X

No Operation

No Operation; Idle after two clock cycles

Notes:

1. Both Banks must be idle otherwise it is an illegal action.

2. The Current State refers only refers to one of the banks, if VCBS selects this bank then the action is illegal. If VCBS selects the bank not being referenced by the Current State

then the action may be legal depending on the state of that bank.

5. Address VCADDR9/AP is used to determine if the Auto Precharge function is activated.

satisfied.