W9751G8JB Datasheet, PDF (12/86 Pages) Winbond – 16M  4 BANKS  8 BIT DDR2 SDRAM

W9751G8JB
7.2.2.2 DLL Enable/Disable
The DLL must be enabled for normal operation. DLL enable is required during power-up initialization,
and upon returning to normal operation after having the DLL disabled. The DLL is automatically
disabled when entering Self Refresh operation and is automatically re-enabled and reset upon exit of
Self Refresh operation. Any time the DLL is enabled (and subsequently reset), 200 clock cycles must
occur before a Read command can be issued to allow time for the internal clock to be synchronized
with the external clock. Failing to wait for synchronization to occur may result in a violation of the tAC
or tDQSCK parameters.
BA1 BA0 A13 A12 A11 A10
A9 A8
A7
A6
A5
A4
A3
A2
A1
A0
Address Field
0
1
0*¹ Qoff RDQS _DQS
OCD program
Rtt
AdditiveWLRatencyBT Rtt D.I.C DLL Extended Mode Register (1)
BA1
0
0
1
1
BA0
0
1
0
1
MRS mode
MRS
EMR (1)
EMR (2)
EMR (3)
A6
A2
0
0
0
1
1
0
1
1
Driver impedance adjustment
A9
A8
A7
OCD Calibration Program
0
0
0
OCD calibration mode exit; matain setting
0
0
1
Drive (1)
0
1
0
1
0
0
1
1
1
Drive (0)
Adjust mode*³
OCD Calibration default*⁴
A12
Qoff
0
Output buffer enabled
1
Output buffer disabled
A10
DQS
0
Enable
1
Disable
A11 RDQS Enable*⁵
0
Disable
1
Enable
A11
(RDQS Enable)
0 (Disable)
0 (Disable)
1 (Enable)
1 (Enable)
A10
(DQS Enable)
0 (Enable)
1 (Disable)
0 (Enable)
1 (Disable)
Rtt (nominal)
ODT disabled
75 ohm
150 ohm
50 ohm*²
A0
DLL Enable
0
Enable
1
Disable
Driver strength control
A1
Output driver
impedance control
Driver size
0
Normal
1
Reduced
100%
60%
Additive Latency
A5 A4 A3
Latency
0
0
0
0
0
0
1
1
0
1
0
2
0
1
1
3
1
0
0
4
1
0
1
5
1
1
0
6
1
1
1
Resesved
RDQS/DM
DM
DM
RDQS
RDQS
Strobe Function Matrix
RDQS
Hi-z
DQS
DQS
Hi-z
DQS
RDQS
DQS
Hi-z
DQS
DQS
DQS
Hi-z
DQS
Hi-z
Notes:
1. A13 reserved for future use and must be set to "0" when programming the EMR (1).
2. Optional for DDR2-667, mandatory for DDR2-800 and DDR2-1066.
3. When Adjust mode is issued, AL from previously set value must be applied.
4. After setting to default, OCD calibration mode needs to be exited by setting A9-A7 to 000. Refer to the section 7.2.3 for
detailed information.
5. If RDQS is enabled, the DM function is disabled. RDQS is active for reads and don‟t care for writes.
Figure 3 – EMR (1)
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Publication Release Date: Oct. 12, 2010
Revision A01