128Mb: x4, x8, x16
SDRAM
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# COMMAND (ACTION)
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 INHIBIT (NOP/Continue previous operation)
NO OPERATION (NOP/Continue previous operation)
Any Command Otherwise Allowed to Bank m
ACTIVE (Select and activate row)
Idle
Row
Activating,
Active, or
Precharging
Read
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
L
H
H
L
ACTIVE (Select and activate row)
(Auto
H
H
L
READ (Select column and start new READ burst)
WRITE (Select column and start WRITE burst)
PRECHARGE
7, 10
7, 11
9
Precharge
Disabled)
Write
L
H
H
L
L
L
H
H
L
ACTIVE (Select and activate row)
(Auto
H
H
L
READ (Select column and start READ burst)
WRITE (Select column and start new WRITE burst)
PRECHARGE
7, 12
7, 13
9
Precharge
Disabled)
Read
L
H
H
L
L
L
H
H
L
ACTIVE (Select and activate row)
(With Auto
Precharge)
H
H
L
READ (Select column and start new READ burst)
WRITE (Select column and start WRITE burst)
PRECHARGE
7, 8, 14
7, 8, 15
9
L
H
H
L
L
Write
L
H
H
L
ACTIVE (Select and activate row)
(With Auto
Precharge)
H
H
L
READ (Select column and start READ burst)
WRITE (Select column and start new WRITE burst)
PRECHARGE
7, 8, 16
7, 8, 17
9
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.
3. Current state definitions:
Idle: The bank has been precharged, and tRP has been met.
Row Active: A row in the bank has been activated, and tRCD has been met. No data bursts/accesses and
no register accesses are in progress.
Read: A READ burst has been initiated, with auto precharge disabled, and has not yet terminated
or been terminated.
Write: A WRITE burst has been initiated, with auto precharge disabled, and has not yet terminated
or been terminated.
Read w/Auto
Precharge Enabled: Starts with registration of a READ command with auto precharge enabled, and ends when
tRP has been met. Once tRP is met, the bank will be in the idle state.
Write w/Auto
Precharge Enabled: Starts with registration of a WRITE command with auto precharge enabled, and ends when
tRP has been met. Once tRP is met, the bank will be in the idle state.
(Continued on next page)
128Mb: x4, x8, x16 SDRAM
128MSDRAM_E.p65 – Rev. E; Pub. 1/02
Micron Technology, Inc., reserves the right to change products or specifications without notice.
©2001, Micron Technology, Inc.
31
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