EM42BM1684RBA
Extended Mode Register Set ( EMRS )
The Extended mode register stores the data enabling or disabling DLL. The value of the extended mode
register is not defined, so the extended mode register must be written after power up for enabling or disabling
DLL. The extended mode register is written by asserting low on /CS, /RAS, /CAS, /WE and high on BA0 ( The
DDR SDRAM should be in all bank precharge with CKE already prior to writing into the extended mode
register. ) The state of address pins A0-A10 and BA1 in the same cycle as /CS, /RAS, /CAS, and /WE going
low is written in the extended mode register. The mode register contents can be changed using the same
command and clock cycle requirements during operation as long as all banks are in the idle state. A0 is used
for DLL enable or disable. High on BA0 is used for EMRS. All the other address pins except A0 and BA0 must
be set to low for proper EMRS operation.
BA1
0
BA0
A12
A11
A10
A9
A8
A7
A6
A5
A4
A3
A2
0
A1
I/O
A0
MRS
RFU*
DLL
*RFU: Reserved for Future Use
Must be set to “0”
An ~ A0
BA0
0
I/O Strength
Full
A1
DLL Enable
Enable
A0
MRS cycle
EMRS
0
1
0
1
1
Half
Disable
Dec. 2010
22/23
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