Rev. 1.1 / May. 2005

13

CKE FUNCTION TRUTH TABLE

Note :

When CKE=L, all DQ and DQS(0~3) must be in Hi-Z state.

1. CKE and /CS must be kept high for a minimum of 200 stable input clocks before issuing any command.

2. All command can be stored after 2 clocks from low to high transition of CKE.

3. Illegal if CK is suspended or stopped during the power down mode.

4. Self refresh can be entered only from the all banks idle state.

5. Disabling CK may cause malfunction of any bank which is in active state.

Current

State

CKEn-

1

CKEn

/CS

/RAS

/CAS

/WE

/ADD

Action

SELF

H

X

XXXXX

INVALID

L

H

H

X

X

X

X

Exit self refresh, enter idle after tSREX

L

H

L

H

H

H

X

Exit self refresh, enter idle after tSREX

LH

L

H

H

L

X

ILLEGAL

LH

L

H

L

X

X

ILLEGAL

L

H

L

L

XXX

ILLEGAL

L

L

XXXXX

NOP, continue self refresh

POWER

H

X

XXXXX

INVALID

L

H

H

X

X

X

X

Exit power down, enter idle

L

H

L

H

H

H

X

Exit power down, enter idle

LH

L

H

H

L

X

ILLEGAL

LH

L

H

L

X

X

ILLEGAL

L

H

L

L

XXX

ILLEGAL

L

L

X

X

X

X

X

NOP, continue power down mode

ALL BANKS

H

H

X

X

X

X

X

See operation command truth table

H

L

LLL

H

X

Enter self refresh

H

L

H

X

X

X

X

Exit power down

H

L

L

H

H

H

X

Exit power down

HL

L

H

H

L

X

ILLEGAL

HL

L

H

L

X

X

ILLEGAL

HL

L

L

H

X

X

ILLEGAL

H

L

LLLL

X

ILLEGAL

L

L

XXXXX

NOP

ANY STATE

OTHER

THAN

ABOVE

H

H

X

X

X

X

X

See operation command truth table

H

L

XXXXX

L

H

XXXXX

INVALID

L

L

XXXXX

INVALID