Preliminary
VG37648041AT
256M:x4, x8, x16
VIS
CMOS Synchronous Dynamic RAM
TRUTH TABLE 4-Current State Bank n - Command to Bank m
(Notes: 1-6; notes appear below and on next page)
CURRENT STATE CS# RAS# CAS# WE#
COMMANDACTION
NOTES
Any
H
L
X
L
L
L
L
L
L
L
L
L
L
L
L
L
L
L
L
L
L
L
L
X
H
X
L
X
H
X
H
L
X
H
X
H
H
L
COMMAND INHBIT (NOP/continue previous operation
NO OPERATION (NOP/continue previous operation)
Any Command Otherwiswe Allowed to Bank m
ACTIVE (select andactivate row)
Idle
Read
Activating,
Active, or
Precharging
H
H
L
READ (select column and start READ burst)
WRITE(select column and start WRITE burst)
PRECHARGE
7
7
L
H
H
L
L
Read
(Auto-
Precharge
Disabled)
L
H
H
L
ACTIVE (select and activate row)
H
H
L
READ (select column and start new READ burst)
WRITE (select column and start WRITE burst)
PRECHARGE
7
7
L
H
H
L
L
Write
(Auto-
Precharge
Disabled)
L
H
H
L
ACTIVE (select and activate row)
H
H
L
READ (select column and start READ burst)
WRITE (select column and start new WRITE burst)
PRECHARGE
7
7
L
H
H
L
L
Read
(With Auto-
Precharge)
L
H
H
L
ACTIVE (select and activate row)
H
H
L
READ (select column and start new READ burst)
WRITE (select column and start WRITE burst)
PRECHARGE
7
7
L
H
H
L
L
Write
(With Auto-
Precharge)
L
H
H
L
ACTIVE (select and activate row)
H
H
L
READ (select column and start READ burst)
WRITE (select column and start new WRITE burst)
PRECHARGE
7
7
L
H
L
NOTE:
1. This table applies when CKEn-1 was HIGH and CKEn Is HIGH (see Truth Table 2) and after tXSR has
been met (if the previous state was self refresh).
2. This table describes alternate bank operation, except where noted, i.e., the current state is for bank n
and the commands shown are those allowed to be issued to bank m (assuming that bank m is in such
a state that the given command is allowable). Exceptions are covered in the notes below.
Document : 1G5-0157
Rev.1
Page65
VML [ VANGUARD INTERNATIONAL SEMICONDUCTOR ]
