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Extended Mode Register 3 (EMR3)
The extended mode register 3 (EMR3) controls functions beyond those controlled by
the mode register. Currently all bits in EMR3 are reserved, as shown in
Figure 44(page 91). The EMR3 is programmed via the LM command and will retain the stored
information until it is programmed again or until the device loses power. Reprogram-
ming the EMR will not alter the contents of the memory array, provided it is performed
correctly.
EMR3 must be loaded when all banks are idle and no bursts are in progress, and the
controller must wait the specified time tMRD before initiating any subsequent opera-
tion. Violating either of these requirements could result in an unspecified operation.
Figure 44: EMR3 Definition
E14
0
1
0
1
Mode Register Set
Mode register (MR)
Extended mode register (EMR)
Extended mode register (EMR2)
Extended mode register (EMR3)
E15
0
0
1
A9
A7 A6 A5 A4 A3
A8
A2 A1 A0
Extended mode
register (Ex)
Address bus
9
7
6
5
4
3
8
2
1
0
A10
A12 A11
BA0
BA1
10
11
12
n
0
14
15
An2
MRS
0
BA21
16
0
Notes: 1. E16 (BA2) is only applicable for densities
≥1Gb, is reserved for future use, and must be
programmed to “0.”
2. Mode bits (En) with corresponding address balls (An) greater than E12 (A12) are re-
served for future use and must be programmed to “0.”
512Mb: x4, x8, x16 DDR2 SDRAM
Extended Mode Register 3 (EMR3)
PDF: 09005aef82f1e6e2
Rev. M 9/08 EN
91
Micron Technology, Inc. reserves the right to change products or specifications without notice.
2004 Micron Technology, Inc. All rights reserved.