9 / 18 page
Rev.01
16Mb SDRAM
9/18
Command
Symbol
CKE
Ignore Command
DESL
No operation
NOP
Truth Table
1. Command Truth Table
H
H
X
n-1
n
/CS
H
L
X
/RAS
X
H
/CAS
X
H
/WE
X
H
BA
X
X
A10
X
X
A9~A0
X
X
Burst stop
BSTH
Read
READ
H
H
X
L
L
X
H
H
H
L
L
H
X
V
X
L
X
V
Read with auto pre-charge
READA
Write
WRIT
H
H
X
L
L
X
H
H
L
L
H
L
V
V
H
L
V
V
Write with auto pre-charge
WRITA
Bank activate
ACT
H
H
X
L
L
X
L
L
H
H
H
H
V
V
H
V
V
V
Pre-charge select bank
PRE
H
L
X
L
H
L
V
L
X
Pre-charge all banks
PALL
Mode register set
MRS
H
H
X
L
L
X
L
L
H
L
L
L
X
L
H
L
X
V
Note : H = High level, L = Low level, X = High or Low level (Don't care), V = Valid data input
Command
Symbol
CKE
2. DQM Truth Table
n-1
n
/CS
Data w rite / output enable
ENB
Data mask / output disable
MASK
H
H
X
H
L
X
Upper byte w rite enable / output enable
BSTH
Read
READ
H
H
X
L
L
X
Read w ith auto pre-charge
READA
Write
WRIT
H
H
X
L
L
X
Write w ith auto pre-charge
WRITA
Bank activate
ACT
H
H
X
L
L
X
Pre-charge select bank
PRE
H
L
X
Pre-charge all banks
PALL
Mode register set
MRS
H
H
X
L
L
X
Note : H = High level, L = Low level, X = High or Low level (Don't care), V = Valid data input
Command
Symbol
CKE
Activating
Any
3. CKE Truth Table
H
L
L
n-1
n
/CS
X
X
L
/RAS
X
X
/CAS
X
X
/WE
X
X
Addr.
X
X
Clock suspend
Idle
REF
L
H
H
X
L
H
X
L
X
L
X
H
X
X
Idle
SELF
Self refresh
H
L
L
L
L
H
L
H
L
H
H
H
X
X
Idle
Power down
H
L
L
X
X
H
X
X
X
X
X
X
X
X
Rem ark H = High level, L = Low level, X = High or Low level (Don't care)
Command
Clock suspend mode entry
Clock suspend mode
Clock suspend mode exit
CBR refresh command
Self refresh entry
Self refresh exit
Pow er dow n entry
Pow er dow n exit
L
H
H
X
X
X
X
( EM481M1622VT )
( EM481M1622VT )