eorex

EM428M1644RTA

Apr. 2007

www.eorex.com

11/20

1. Command Truth Table

CKE

Command

Symbol

n-1

n

/CS

/RAS

/CAS

/WE

BA0,

BA1

A10

A12~A0

Ignore Command

DESL

H

X

H

X

X

X

X

X

X

No Operation

NOP

H

X

L

H

H

H

X

X

X

Burst Stop

BSTH

H

X

L

H

H

L

X

X

X

Read

READ

H

X

L

H

L

H

V

L

V

Read with Auto Pre-charge

READA

H

X

L

H

L

H

V

H

V

Write

WRIT

H

X

L

H

L

L

V

L

V

Write with Auto Pre-charge

WRITA

H

X

L

L

H

H

V

H

V

Bank Activate

ACT

H

X

L

L

H

H

V

V

V

Pre-charge Select Bank

PRE

H

X

L

L

H

L

V

L

X

Pre-charge All Banks

PALL

H

X

L

L

H

L

X

H

X

Mode Register Set

MRS

H

X

L

L

L

L

L

L

V

H = High level, L = Low level, X = High or Low level (Don't care), V = Valid data input

2. CKE Truth Table

CKE

Item

Command

Symbol

n-1

n

/CS

/RAS

/CAS

/WE

Addr.

Idle

CBR Refresh Command

REF

H

H

L

L

L

H

X

Idle

Self Refresh Entry

SELF

H

L

L

L

L

H

X

L

H

L

H

H

H

X

Self Refresh

Self Refresh Exit

L

H

H

X

X

X

X

Idle

Power Down Entry

H

L

X

X

X

X

X

Power Down

Power Down Exit

L

H

X

X

X

X

X

Remark H = High level, L = Low level, X = High or Low level (Don't care)