Datasheet

Write Leveling Mode Exit
The following sequence describes how the Write Leveling Mode should be exited:
1. After the last rising strobe edge (see ~T0), stop driving the strobe signals (see ~Tc0). Note: From now on,
DQ pins are in undefined driving mode, and will remain undefined, until t
MOD
after the respective MRS
command (Te1).
2. Drive ODT pin low (t
IS
must be satisfied) and continue registering low (see Tb0).
3. After the R
TT
is switched off, disable Write Level Mode via MRS command (see Tc2).
4. After t
MOD
is satisfied (Te1), any valid command may be registered. (MRS commands may be issued after
t
MRD
(Td1).
t
IS
DESDES DES DES DES DES DES MRS DES MRS DES VALID
CK#
CK
CMD
ODT
DQS#
DQS
ADDR
t
ADCmax
t
ADCmin
ODTLoff
t
WLO
t
MRD
MR1 MRx VALID
RTT_NOM
All DQs
DQs
T1 T2 Ta0 Tb0 Tc0 Tc1 Tc2 Td0T0
R
TT_NOM
R
TT_PARK
Td1 Te0 Te1
t
MOD
result = 1
RTT_NOM
DQS, DQS#
Figure 14. Write Leveling Exit
AS4C256M16D4
Confidential
- 35 of 201 -
Rev.1.0 Aug.2019