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

White Electronic Designs

WED3DL328V

June, 2002

Rev. 1

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

Current State

CKE

Command

Action

Notes

Previous

Cycle

Current

Cycle

CE#

RAS#

CAS#

WE# BA0-1 A10-11

Self Refresh

H

X

X

X

X

X

X

X

INVALID

1

L

H

H

X

X

X

X

X

Exit Self Refresh with Device Deselect

2

L

H

L

H

H

H

X

X

Exit Self Refresh with No Operation

2

L

H

L

H

H

L

X

X

ILLEGAL

2

L

H

L

H

L

X

X

X

ILLEGAL

2

L

H

L

L

X

X

X

X

ILLEGAL

2

L

L

X

X

X

X

X

X

Maintain Self Refresh

Power Down

H

X

X

X

X

X

X

X

INVALID

1

L

H

H

X

X

X

X

X

Power Down Mode exit, all banks idle

2

L

H

L

X

X

X

X

X

ILLEGAL

2

H

X

L

H

L

L

X

Maintain Power Down Mode

2

All Banks Idle

H

H

H

X

X

X

Refer to the Idle State section of the

Current State Truth Table

3

H

H

L

H

X

X

H

H

L

L

H

X

H

H

L

L

L

H

X

X

CBR Refresh

H

H

L

L

L

L

OP Code

Mode Register Set

4

H

L

H

X

X

X

Refer to the Idle State section of the

Current State Truth Table

3

H

L

L

H

X

X

H

L

L

L

H

X

H

L

L

L

L

H

X

X

Entry Self Refresh

4

H

H

L

L

L

L

OP Code

Mode Register Set

L

X

X

X

X

X

X

X

Power Down

4

Any State other

than listed above

H

H

X

X

X

X

X

X

Refer to the Operations in the Current

State Truth Table

H

L

X

X

X

X

X

X

Begin Clock Suspend next cycle

5

L

H

X

X

X

X

X

X

Exit Clock Suspend next cycle

L

L

X

X

X

X

X

X

Maintain Clock Suspend

NOTES:

1. For the given Current State CKE must be low in the previous cycle.

command other than Exit is issued.

3. The address inputs (A11-0) depend on the command that is issued. See the Idle State section of the Current State Truth Table for more information.

4. The Power Down Mode, Self Refresh Mode, and the Mode Register Set can only be entered from the all banks idle state.

Must be a legal command as defined in the Current State Truth Table.

CLOCK ENABLE (CKE) TRUTH TABLE