K4J55323QG Datasheet, PDF (17/53 Pages) Samsung semiconductor – 256Mbit GDDR3 SDRAM

K4J55323QG
256M GDDR3 SDRAM
7.6 Clock frequency change sequence during the device operation
Both existing tCK and desired tCK are in DLL-On mode
- Change frequency from existing frequency to desired frequency
- Issue Precharge All Banks command
- Issue MRS command to reset the DLL while other fields are valid and required 20K tCK to lock the DLL
- Issue Precharge All Banks command. Issue at least Auto-Refresh command
CK
CK
CMD NOP
NOP
NOP
NOP
NOP
NOP
PRE
MRS
PRE
NOP
AR
NOP
Frequency
Change
tFCHG
All Banks
Precharge
DLL
Reset
All Banks
Precharge
tRP
tMRD
20tCK (DLL locking time)
Existing tCK is in DLL-on mode while desired tCK is in DLL-off mode
- Issue Precharge All Banks command
- Issue EMRS command to disable the DLL
- Issue Precharge All Banks command
- Change the frequency from existing to desired.
- Issue Auto-Refresh command at least two. Issue MRS command
CK
CK
CMD PRE
EMRS
PRE
NOP
NOP
NOP
AR
MRS
NOP
NOP
NOP
NOP
All Banks
Precharge
DLL
OFF
All Banks
Precharge
tRP
tMRD
Frequency
Change
tFCHG
Clock frequency change in case existing tCK is in DLL-off mode while desired tCK is in DLL-on mode
- Issue Precharge All Banks command and issue EMRS command to disable the DLL.
- Issue Precharge All Banks command.
- Change the clock frequency from existing to desired
- Issue Precharge All Banks command.
- Issue EMRS command to enable the DLL
- Issue MRS command to reset the DLL and required 20K tCK to lock the DLL.
- Issue Precharge All Banks command.
- Issue Auto-Refresh command at least two
CK
CK
CMD PRE
EMRS
PRE
NOP
NOP
NOP
PRE
EMRS
MRS
PRE
NOP
AR
All Banks
Precharge
DLL
OFF
All Banks
Precharge
tRP
tMRD
Frequency
Change
tFCHG
All Banks
DLL
Precharge
On
DLL
Reset
All Banks
Precharge
tRP
tMRD
tMRD
20tCK (DLL locking time)
17 of 53
Rev. 1.1 November 2005