W632GG6KB
Publication Release Date: Jan. 03, 2017
Revision: A06
- 27 -
8.7.2
DLL “off” to DLL “on” Procedure
To switch from DLL “off” to DLL “on” (with required frequency change) during Self-Refresh:
1. Starting from Idle state (All banks pre-charged, all timings fulfilled and DRAMs On-die Termination
resistors (R
TT
) must be in high impedance state before Self-Refresh mode is entered.)
2. Enter Self Refresh Mode, wait until t
CKSRE
satisfied.
3. Change frequency, in guidance with section 8.8
“Input clock frequency change”
on page 28.
4. Wait until a stable clock is available for at least (t
CKSRX
) at DRAM inputs.
5. Starting with the Self Refresh Exit command, CKE must continuously be registered HIGH until
t
DLLK
timing from subsequent DLL Reset command is satisfied. In addition, if any ODT features
were enabled in the mode registers when Self Refresh mode was entered, the ODT signal must
continuously be registered LOW until t
DLLK
timings from subsequent DLL Reset command is
satisfied. If both ODT features are disabled in the mode registers when Self Refresh mode was
entered, ODT signal can be registered LOW or HIGH.
6. Wait t
XS
, then set MR1 bit A0 to “0” to enable the DLL.
7. Wait t
MRD
, then set MR0 bit A8 to “1” to start DLL Reset.
8. Wait t
MRD
, then set Mode Registers with appropriate values (especially an update of CL, CWL and
WR may be necessary. After t
MOD
satisfied from any proceeding MRS command, a ZQCL
command may also be issued during or after t
DLLK
.)
9. Wait for t
MOD
, then DRAM is ready for next command (Remember to wait t
DLLK
after DLL Reset
before applying command requiring a locked DLL!). In addition, wait also for t
ZQ
oper in case a
ZQCL command was issued.
TIME BREAK
DON'T CARE
T0
Ta0
Ta1
Tb0
Tc0
Td0
Te0
Tf1
Tg0
Th0
CK#
CK
CKE
Command
NOP
SRX
*5
MRS
*6
MRS
*7
MRS
*8
VALID
*9
ODT
NOP
SRE
*2
VALID
*1
t
CKSRE
t
CKSRX
*4
t
MRD
t
MRD
t
CKESR
ODT: Static LOW in case Rtt_Nom and Rtt_WR is enabled, otherwise static Low or High
Notes:
1. Starting with idle state
2. Enter SR
3. Change Frequency
4. Clock must be stable t
CKSRX
5. Exit SR
6. Set DLL on by MR1 A0 = 0
7. Update Mode registers
8. Any valid command
Tc1
t
DLLK
t
XS
*3
O 1 x
t
CK
Figure 11
– DLL Switch Sequence from DLL Off to DLL On