Datasheet

Timing Waveforms
Figure 8. Initialization sequence after power-up
CK
CK#
t
CH
CKE
Command
t
CL
t
IS
ODT
t
IS
NOP
PRE
ALL
EMR
S
MRS
PRE
ALL
REF
REF
MRS
EMR
S
EMR
S
ANY
CMD
400ns
t
RP
t
MRD
t
MRD
t
RP
t
MRD
Follow OCD Flowchart
t
OIT
min 200 Cycle
DLL
ENABLE
DLL
RESET
OCD
Default
OCD
CAL.MOD
E EXIT
NOTE 1: To guarantee ODT off, V
REF
must be valid and a LOW level must be applied to the ODT pin.
t
RFC
t
RFC
Figure 9. OCD drive mode
CK#
Hi-Z
CK
DQS
DQS#
DQs HIGH for Drive(1)
CMD
OCD calibration mode exit
t
OIT
Enter Drive mode
EMRS NOP NOP NOP
EMRS
DQ
DQS HIGH & DQS# LOW for Drive(1), DQS LOW & DQS# HIGH for Drive(0)
DQs LOW for Drive(0)
t
OIT
Hi-Z
NOTE : Drive mode, both Drive(1) and Drive(0), is used for controllers to measure DDR2 SDRAM Driver
impedance.In this mode, all outputs are driven out t
OIT
after "enter drive mode" command and all output
drivers are turned-off t
OIT
after "OCD calibration mode exit" command.
AS4C64M16D2A-25BIN
AS4C64M16D2A-25BCN
Confidential
- 35 of 62 -
Rev.1.1 October 2017