10 SDRAM CONTROLLER (SDRAMC)
S1C33L26 TECHNICAL MANUAL
Seiko Epson Corporation
10-5
Timing setup
The following parameters can be configured according to the SDRAM specifications.
SDCLK
Command
SDBA[1:0]
SDA[12:11, 9:0]
SDA10
DQ[15:0]
ACTV
NOP
NOP
NOP NOP NOP PRE
READ
BA
BA
BA
ROW
COL
ROW
ACTV
ROW
BA
ROW
BA
ROW
ROW
DATA DATA
t
RCD
t
RC
t
RP
t
RAS
CAS latency
NOP ACTV
BA
BKsel
SDCLK
Command
SDCKE
SDBA[1:0]
SDA10
SDA[12:11, 9:0]
DQ[15:0]
SELF
NOP PALL NOP
Self-refresh mode
t
RFC
t
XSR
+ 1 cycle
t
RP
NOP
4.2.3 SDRAM Timing Parameters
Figure 10.
(1) CAS Latency
CAS latency refers to the number of SDCLK clock cycles that run until data is output from the SDRAM
after the READ command is issued. In this SDRAM interface, CAS latency can be set from 1 to 3 using
CAS[1:0]/SDRAMC_APP register.
4.2.3 CAS Latency Settings
Table 10.
CAS[1:0]
CAS latency
0x3
3
0x2
2
0x1
1
0x0
Reserved
(Default: 0x2)
(2) t
RC
, t
RFC
, t
XSR
t
RC
: ACTIVE to ACTIVE command cycle time
t
RFC
: Auto-refresh cycle time
t
XSR
: Self-refresh end to ACTIVE command period
These timing parameters can be set from 1 to 16 cycles in SDCLK using T80NS[3:0]/SDRAMC_CFG reg-
ister.