EM42BM1684RBA
4. Command Truth Table for CKE
Current State
C
H
KE /CS /R /C /W
Addr.
X
Action
X
H
X
H
X
X
X
X
X
X
INVALID
L
X
Exist Self-Refresh
L
L
L
H
H
H
L
L
L
H
H
H
H
H
L
H
L
X
X
X
Exist Self-Refresh
ILLEGAL
Self Refresh
X
ILLEGAL
L
L
H
L
L
X
X
H
L
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
ILLEGAL
NOP(Maintain self refresh)
INVALID
H
L
X
H
Exist Power down
Both bank
precharge
power down
L
L
L
H
H
H
L
L
L
H
H
H
H
H
L
H
L
X
X
X
X
Exist Power down
ILLEGAL
ILLEGAL
L
L
H
L
H
L
L
L
L
X
X
H
L
L
X
X
X
H
H
X
X
X
X
H
H
X
X
X
X
H
L
X
X
X
X
X
X
ILLEGAL
NOP(Maintain Power down)
H
H
H
H
Refer to function true table
Enter power down mode(Note 3)
Enter power down mode(Note 3)
L
ILLEGAL
H
H
L
L
L
L
L
H
L
L
H
X
H
X
RA
ILLEGAL
Row active/Bank active
Enter self-refresh(Note 3)
All Banks
Idle
H
H
H
L
L
L
L
X
L
L
L
X
L
L
L
X
H
L
X
L
L
Op-Code
Op-Code
X
Mode register access
L
Special mode register access
Refer to current state
X
H
X
Any State Other
than Listed above
H
X
X
X
X
X
Refer to command truth table
H = High level, L = Low level, X = High or Low level (Don't care)
Notes 1: After CKE’s low to high transition to exist self refresh mode.And a time of tRC(min) has to be Elapse after
CKE’s low to high transition to issue a new command.
Notes 2: CKE low to high transition is asynchronous as if restarts internal clock.
Notes 3: Power down and self refresh can be entered only from the idle state of all banks.
Dec. 2010
17/23
www.eorex.com
EOREX [ EOREX CORPORATION ]
