256MB, 512MB (x64, DR)
144-PIN SDRAM SODIMM
Commands
The Truth Table provides a quick reference of avail-
able commands. This is followed by written descrip-
description of commands and operations, refer to the
128Mb or 256Mb SDRAM component data sheet.
tion of each command. For
a more detailed
Table 9:
Truth Table – SDRAM Commands and DQMB Operation
CKE is HIGH for all commands shown except SELF REFRESH
NAME (FUNCTION)
CS# RAS# CAS# WE# DQMB
ADDR
DQ
NOTES
H
X
H
L
X
H
H
L
X
H
H
H
X
X
X
X
X
X
X
X
COMMAND INHIBIT (NOP)
L
L
L
X
NO OPERATION (NOP)
Bank/Row
Bank/Col
1
2
ACTIVE (select bank and activate row)
READ (select bank and column, and start READ burst)
L/H8
H
L/H8
X
L
H
L
L
Bank/Col Valid
2
WRITE (select bank and column, and start WRITE burst)
L
L
L
H
L
H
H
L
L
L
X
Code
X
Active
BURST TERMINATE
X
X
X
3
PRECHARGE (deactivate row in bank or banks)
L
H
X
4, 5
AUTO REFRESH or SELF REFRESH
(enter self refresh mode)
L
–
–
L
–
–
L
–
–
L
–
–
X
L
Op-code
X
6
7
7
LOAD MODE REGISTER
–
–
Active
High-Z
Write enable/output enable
Write inhibit/output High-Z
H
NOTE:
1. A0–A11 (256MB) or A0–A12 (512MB) provide device row address, and BA0, BA1 determine which device bank is made
active.
2. A0–A9 (256MB and 512MB) provide device column address; A10 HIGH enables the auto precharge feature (nonpersis-
tent), while A10 LOW disables the auto precharge feature; BA0, BA1 determine which device bank is being read from or
written to.
3. A10 LOW: BA0, BA1 determine which device bank is being precharged. A10 HIGH: all device banks are precharged and
BA0, BA1 are “Don’t Care.”
4. This command is AUTO REFRESH if CKE is HIGH, SELF REFRESH if CKE is LOW.
5. Internal refresh counter controls row addressing; all inputs and I/Os are “Don’t Care” except for CKE.
6. A0–A11 define the op-code written to the mode register; for the 256MB and 512MB, A12 should be driven low.
7. Activates or deactivates the DQs during WRITEs (zero-clock delay) and READs (two-clock delay).
pdf: 09005aef807924d2, source: 09005aef807924f1
SDF16C32_64x64HG.fm - Rev. E 4/06 EN
Micron Technology, Inc., reserves the right to change products or specifications without notice.
©2006 Micron Technology, Inc. All rights reserved.
11
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