Hynix HMP125U6EFR8C-S6 ユーザーズマニュアル

5

If OCD calibration is not used, EMR OCD Default command (A9=A8= A7=1) followed by EMR OCD Calibra-
tion Mode Exit command (A9=A8=A7=0) must be issued with other operating parameters of EMR.

13. The DDR2 SDRAM is now ready for normal operation.

*1) To guarantee ODT off, VREF must be valid and a LOW level must be applied to the ODT pin.
*2) Sequence 5 and 6 may be performed between 8 and 9.

For application flexibility, burst length, burst type, CAS latency, DLL reset function, write recovery time(WR) 
are user defined variables and must be programmed with a Mode Register Set(MRS) command. Additionally, 
DLL disable function, driver impedance, additive CAS latency, ODT(On Die Termination), single-ended 
strobe, and OCD(off chip driver impedance adjustment) are also user defined variables and must be pro-
grammed with an Extended Mode Register Set (EMRS) command. Contents of the Mode Register(MR) or 
Extended Mode Registers(EMR(#)) can be altered by re-executing the MRS and EMRS Commands. Even if 
the user chooses to modify only a subset of the MR or EMR(#) variables, all variables within the addressed 
register must be redefined when the MRS or EMRS commands are issued. 

MR, EMR and Reset DLL do not affect array contents, which means reinitialization including those can be 
executed any time after power-up without affecting array contents.

/CK

CK

CKE

Command

PRE
ALL

PRE
ALL

EMR

MR

REF

REF

MR

EMR

EMR

ANY
CMD

DLL
ENABLE

DLL
RESET

OCD
Default

OCD
CAL. MODE
EXIT

Follow OCD
Flowchart

400ns

tRFC

tRFC

tRP

tRP

tMRD

tMRD

tMRD

tOIT

min. 200 Cycle

NOP

ODT

tCL

tCH

tIS

tIS