EM47EM1688MBB
1. Command Truth Table
CKE
n-1
BA0~
BA2
A12,
A10~A0
Command
Symbol
/CS /RAS
/CAS
/WE
A10
N
Device Deselect
No Operation
DES
NOP
RD
H
H
H
H
H
H
H
H
H
H
H
L
L
L
L
X
H
H
H
H
X
H
L
X
H
H
H
H
X
X
V
L
L
L
X,X
V,V
V
Read (fixed BL8/BC4)
Read (BC4, OTF)
Read (BL8, OTF)
BA
BA
BA
V,CA
L,CA
H,CA
RDS4
RDS8
L
L
Read with Auto Pre-
charge (fixed BL8/BC4)
RDA
H
H
L
H
L
H
BA
H
V,CA
Read with Auto Pre-
charge (BC4, OTF)
Read with Auto Pre-
charge (BL8, OTF)
RDAS4
RDAS8
H
H
H
H
L
L
H
H
L
L
H
H
BA
BA
H
H
L,CA
H,CA
Write (fixed BL8/BC4)
Write (BC4, OTF)
Write (BL8,OTF)
WR
H
H
H
H
H
H
L
L
L
H
H
H
L
L
L
L
L
L
BA
BA
BA
L
L
L
V,CA
L,CA
H,CA
WRS4
WRS8
Write with Auto Pre-
charge (fixed BL8/BC4)
WRA
H
H
L
H
L
L
BA
H
V,CA
Write with Auto Pre-
charge (BC4, OTF)
Write with Auto Pre-
charge (BL8, OTF)
WRAS
4
WRAS
8
H
H
H
H
L
L
H
H
L
L
L
L
BA
BA
H
H
L,CA
H,CA
Bank Activate
ACT
PRE
PREA
MRS
REF
H
H
H
H
H
H
H
H
H
H
H
L
L
L
L
L
L
L
L
L
H
H
H
L
H
L
L
L
BA
BA
V
RA
Pre-charge Single Bank
Pre-charge All Banks
Mode Register Set
Refresh
L
V,V
V,V
H
BA
OP Code
L
L
L
L
L
L
H
H
X
H
X
H
V
V
X
V
X
V
V
V
X
V
X
V
V,V
V,V
X,X
V,V
X,X
V,V
Self Refresh entry
SRE
H
L
X
H
X
H
X
H
X
H
Self Refresh Exit
SRX
L
H
H
H
L
L
L
H
L
Power Down Entry
PDE
H
H
H
H
H
L
L
L
X
H
H
H
X
H
H
H
X
H
L
X
V
X
X
X
V
H
L
X,X
V,V
X,X
X,X
Power Down Exit
PDX
L
ZQ Calibration Long
ZQ Calibration Short
ZQCL
ZQCS
H
H
L
H = High level, L = Low level, X = Don't care, V = Valid, BA=Bank Address, CA=Column Address, RA=Row Address
Oct. 2013
25/38
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