VG36644041DT / VG36648041DT / VG36641641DT
CMOS Synchronous Dynamic RAM
VIS
2.Truth Table
2.1 Command Truth Table
CKE
n - 1
A11
A9 - A0
FUNCTION
Symbol
n
X
X
X
X
X
X
X
X
X
X
X
H
L
CS
H
L
RAS CAS WE
BA
X
X
L
A10
X
X
L
Device deselect
No operation
DESL
NOP
H
H
H
H
H
H
H
H
H
H
H
H
H
X
H
L
X
H
L
X
H
L
X
X
V
V
V
V
V
V
X
X
X
X
X
Mode register set
Bank activate
MRS
L
ACT
L
L
H
L
H
H
H
L
V
V
V
V
V
V
X
X
X
X
V
L
Read
READ
READA
WRIT
WRITA
PRE
L
H
H
H
H
L
Read with auto precharge
Write
L
L
H
L
L
L
Write with auto precharge
Precharge select bank
Precharge all banks
Burst stop
L
L
L
H
L
L
H
H
H
L
L
PALL
BST
L
L
L
H
X
X
X
L
H
L
L
CBR (Auto) refresh
Self refresh
REF
L
H
H
SELF
L
L
L
2.2 DQM Truth Table
CKE
DQM
FUNCTION
Data write/output enable
Data mask/output disable
Symbol
ENB
n - 1
n - 1
X
H
H
L
MASK
X
H
2.3 CKE Truth Table
CKE
n - 1
Add -
ress
Current State
Function
Symbol
n
CS
X
X
X
L
RAS CAS
WE
X
Activating
Any
Clock suspend mode entry
Clock suspend
H
L
L
L
X
X
X
L
X
X
X
L
X
X
X
X
X
X
X
X
X
X
Clock suspend
Idle
Clock suspend mode exit
CBR refresh command
Self refresh entry
L
H
H
L
X
REF
H
H
L
H
H
H
X
Idle
SELF
L
L
L
Self refresh
Self refresh exit
H
H
L
L
H
X
X
X
H
X
X
X
L
H
X
X
Idle
Power down entry
Power down exit
H
L
X
Power down
H
X
H : High level, L : Low level
X : High or Low level (Don’t care), V : Valid Data input
Document :1G5-0177
Rev.2
Page10