21.4.2 Refresh Controller Bus Timing
Refresh controller bus timing is shown as follows:
•
DRAM bus timing
Figures 21-10 to 21-15 show the DRAM bus timing in each operating mode.
•
PSRAM bus timing
Figures 21-16 and 21-17 show the pseudo-static RAM bus timing in each operating mode.
Figure 21-10 DRAM Bus Timing (Read/Write): Three-State Access
— 2
WE
Mode —
ø
A
9
to A
1
AS
CS
(
RAS
)
RD
(
CAS
)
HWR
(
UW
),
LWR
( )
LW
(read)
HWR
(
UW
),
LWR
( )
LW
(write)
RFSH
D
15
to D
0
(read)
D
15
to D
0
(write)
T
1
T
2
T
3
t
AD
t
AD
t
RAH
t
RAD1
t
AS1
t
ASD
t
AS1
t
RAC
t
ASD
t
AA
t
CAC
t
RAD3
t
RP
t
SD
t
CRP
t
SD
t
WDH
t
RDS
t
RDH
t
WDS3
t
CAS
3
696
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