EM44CM0884LBA
Extended Mode Register Set EMRS(1 )
The EMRS (1) is written by asserting low on /CS, /RAS, /CAS, /WE,BA1 and high on BA0 ( The DDR2 should
be in all bank pre-charge with CKE already prior to writing into the extended mode register. ) The extended
mode register EMRS(1) stores the data for enabling or disabling the DLL, output driver strength, additive
latency, OCD program, ODT, DQS and output buffers disable, RQDS and RDQS enable. The default value of
the extended mode register EMRS(1) is not defined, therefore the extended mode register must be written after
power-up for proper operation. The mode register set command cycle time (tMRD) must be satisfied to complete
the write operation to the EMRS(1). Mode register contents can be changed using the same command and
clock cycle requirements during normal operation when all banks are in pre-charge state.
BA1
0
BA2
0
BA0
1
A13
0
A12
Qoff
A11
A10
A9
A8
A7
A6
Rtt
A5
A4
A3
A2
Rtt
A1
A0
RDQS
/DQS
OCD program
Additive latency
DIC
DLL
DLL
A0
A0
(Output Buffer)
Enabled
Qoff
A12
RDQS
enable
A11
A11
/DQS
A10
0
Enable
Disable
00
11
0
1
Enable
Disable
Disable
Enable
0
0
Disabled
1
11
Output Driver
A1
Impedance Control
Normal (100%)
Weak (60%)
0
1
OCD Calibration Program
OCD Calibration mode exit
A9 A8 A8
AA77
0
0
0
0
0
0
0
0
0
0
Drive (1)
Drive (0)
0
0
1
1
1
Rtt
Rtt
A6
0
A2
A2
1
00
ODT Disable
ODT Disable
0
1
0
1
0
1
0
0
1
1
(*1A)djust mode (*1)
0
1
75 ohm
75 ohm
0
OCD Calibration default (*2)
(*2)
1
1
1
150 ohm
150 ohm
1
50 ohm *
50 ohm
1
*1:
*2:
e applied.
When adjust mode is issued, AL from previously set value must b
After setting to default, OCD mode needs to be exited by settin
-
A7 to 000.
g A9
-
Refer to the section Off
Chip Driver (OCD) impedance adjustment for detail
information
Additive Latency
A5
0
A4
0
A3
0
0
1
0
1
0
1
0
1
MRS Mode
MRS
BA1
0
BA0
0
1
0
0
2
0
1
EMRS(1)
EMRS(2)
0
1
3
0
1
1
0
4
1
0
EMRS(3) Reserved
1
1
5
1
0
6
1
1
Reserved
1
1
Note1. For DDR2-1066, the “Rtt” must be set to 50 ohm (A2 = 1 & A6 = 1).
Note2. A13 is reserved for future use.
Note3. BA2 is reserved for future use.
Dec. 2014
24/28
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