Figure 42: DLL Enable Mode to DLL Disable Mode
Command
T0
T1
Ta0
Ta1
Tb0
Tc0
7
6
Td0
Td1
Te0
Te1
Tf0
CK
CK#
ODT9
Valid1
Don’t Care
Valid1
SRE3
NOP
MRS2
NOP
SRX4
MRS5
Valid1
NOP
Indicates A Break in
Time Scale
tMOD
tCKSRE
tMOD
tXS
tCKESR
CKE
tCKSRX8
Notes: 1. Any valid command.
2. Disable DLL by setting MR1[0] to 1.
3. Enter SELF REFRESH.
4. Exit SELF REFRESH.
5. Update the mode registers with the DLL disable parameters setting.
6. Starting with the idle state, RTT is in the High-Z state.
7. Change frequency.
8. Clock must be stable tCKSRX.
9. Static LOW in the case that RTT,nom or RTT(WR) is enabled; otherwise, static LOW or HIGH.
A similar procedure is required for switching from the DLL disable mode back to the
DLL enable mode. This also requires changing the frequency during self refresh mode
1. Starting from the idle state (all banks are precharged, all timings are fulfilled, ODT
is turned off, and RTT,nom and RTT(WR) are High-Z), enter self refresh mode.
2. After tCKSRE is satisfied, change the frequency to the new clock rate.
3. Self refresh may be exited when the clock is stable with the new frequency for
tCKSRX. After tXS is satisfied, update the mode registers with the appropriate val-
ues. At a minimum, set MR1[0] to 0 to enable the DLL. Wait tMRD, then set MR0[8]
to 1 to enable DLL RESET.
4. After another tMRD delay is satisfied, then update the remaining mode registers
with the appropriate values.
5. The DRAM will be ready for its next command in the DLL enable mode after the
greater of tMRD or tMOD has been satisfied. However, before applying any com-
mand or function requiring a locked DLL, a delay of tDLLK after DLL RESET must
be satisfied. A ZQCL command should be issued with the appropriate timings met.
2Gb: x4, x8, x16 DDR3 SDRAM
Commands
PDF: 09005aef826aaadc
2Gb_DDR3_SDRAM.pdf – Rev. K 04/10 EN
120
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