iPEM
4.2 Gb SDRAM-DDR2
Austin Semiconductor, Inc.
AS4DDR264M64PBG1
EXTENDED MODE REGISTER (EMR)
until it is programmed again or the device loses power.
Reprogramming the EMR will not alter the contents of the
memory array, provided it is performed correctly.
The extended mode register controls functions beyond
those controlled by the mode register; these additional
functions are DLL enable/disable, output drive strength, on
die termination (ODT) (RTT), posted AL, off-chip driver
impedance calibration (OCD), DQS# enable/disable,
RDQS/RDQS# enable/disable, and output disable/enable.
These functions are controlled via the bits shown in Figure
7. The EMR is programmed via the LOAD MODE (LM)
command and will retain the stored information
The EMR 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 operation. Violating either
of these requirements could esult in unspecified operation.
FIGURE 7 – EXTENDED MODE REGISTER DEFINITION
1
3
2
2
BA2 BA1 BA0 An A12 A11 A10 A9 A8 A7 A6 A5 A4 A3 A2 A1 A0
Address bus
Extended mode
register (Ex)
16 15 14
n
12 11 10
Out
9
8
7
6
5
4
3
2
1
0
2
0
MRS
RTT
Posted CAS#
0
OCD Program
R
TT ODS DLL
RDQS DQS#
Outputs
Enabled
Disabled
E0
0
DLL Enable
Enable (normal)
Disable (test/debug)
E12
0
E6 E2 RTT (Nominal)
1
1
0
0
1
1
0
1
0
1
RTT disabled
75:
150:
50:
E11 RDQS Enable
E1 Output Drive Strength
0
1
No
(100%)
0
1
Full
Reduced
Yes
(40-60%)
Posted CAS# Additive Latency (AL)4
E10 DQS# Enable
E5 E4 E3
0
1
Enable
Disable
0
0
0
0
0
1
1
1
1
0
0
1
1
0
0
1
1
0
1
0
1
0
1
0
1
1
2
E9 E8 E7 OCD Operation
3
0
0
0
1
1
0
0
1
0
1
0
1
0
0
1
OCD exit
Reserved
Reserved
Reserved
4
5
6
Reserved
Enable OCD defaults
Mode Register Set
Mode register (MR)
E15 E14
0
1
0
1
0
0
1
1
Extended mode register (EMR)
Extended mode register (EMR2)
Extended mode register (EMR3)
Notes:
1.During initialization, all three bits must be set to “1” for OCD default state, then must be set to “0” before
initialization is finished, as detailed in the initialization procedure.
2.E13 (A13) must be programmed to “0” and is reserved for future use.
3.E16 must be programmed to “0” and is reserved for future use.
4.Not all AL options are supported in any individual speed grade.
Austin Semiconductor, Inc.
● Austin, Texas ● 512.339.1188 ● www.austinsemiconductor.com
AS4DDR264M64PBG1
Rev. 0.5 06/08
10
AUSTIN [ AUSTIN SEMICONDUCTOR ]
