10 SDRAM CONTROLLER (SDRAMC)
S1C33L26 TECHNICAL MANUAL
Seiko Epson Corporation
10-11
Write cycle
When writing to the SDRAM, data are always written in a single operation.
Parameter setting example: CAS latency = 2, t
RCD
= 2 cycles, t
RAS
= 4 cycles, t
RP
= 2 cycles
SDCLK
Command
SDCKE
#SDCS
#SDRAS
#SDCAS
#SDWE
SDBA[1:0]
SDA10
SDA[12:11, 9:0]
DQMH/DQML
DQ[15:0]
ACTV
H
NOP
PRE NOP
READ
BA
BA
ROW1
D
(n)
D
(n+1)
D
(m)
t
RCD
t
RP
CAS
latency
ROW1
COLn
BA
WRIT
PRE
BA
COLm
BA
5.4.3 Burst Read to Single Write (same page)
Figure 10.
Bank interleaved access
Multiple banks (up to four banks) can be activated at the same time. This makes it possible to access the
SDRAM successively, one bank after another without issuing the ACTV (Active) command.
Parameter setting example: CAS latency = 2, t
RCD
= 2 cycles, t
RAS
= 4 cycles, t
RP
= 2 cycles
SDCLK
Command
SDCKE
#SDCS
#SDRAS
#SDCAS
#SDWE
SDBA[1:0]
SDA10
SDA[12:11, 9:0]
DQMH/DQML
DQ[15:0]
Bank 1
Bank 2
ACTV
H
NOP
NOP
ACTV
READ
READ
READ
BA1
BA1
ROW2
D
(n)
D
(n+1)
t
RP
(Bank 1 cannot be accessed.)
CAS
latency
ROW2
ROW1
ROW1
Active
Read
Precharge
Active
Read
COLn
BA2
COLm
BA1
COLl
BA2
PRE NOP
NOP
BA1
D
(m)
D
(m+1)
D
(l)
ACTV
BA1
ROW3
ROW3
5.4.4 Bank Interleaved Access
Figure 10.