10 SDRAM CONTROLLER (SDRAMC)
10-8
Seiko Epson Corporation
S1C33L26 TECHNICAL MANUAL
5.1.1 Data Write Address to Execute the MRS/EMRS Command
Table 10.
CPU address
A15
A14
A13
A12
A11
A10
A9
A8
A7
A6
A5
A4
A3
A2
A1
SDRAM address
BA1
BA0
SDA12 SDA11 SDA10 SDA9
SDA8
SDA7
SDA6
SDA5
SDA4
SDA3
SDA2
SDA1
SDA0
MRS
Mode
Reserved
WB
Test mode
CAS latency
BT
Burst length
CAS latency = 1
0
0
0
0
0
1
0
0
0
0
1
0
0
0
1
CAS latency = 2
0
0
0
0
0
1
0
0
0
1
0
0
0
0
1
CAS latency = 3
0
0
0
0
0
1
0
0
0
1
1
0
0
0
1
EMRS
Mode
Reserved
DS
TCSR
PASR
1
0
0
0
0
0
0
0
0
See the SDRAM specification.
For example, to execute an MRS command with CAS latency = 2, write any value to address 0x10000442
(when the SDRAM is mapped to Area 19) after writing 0x14 to the SDRAMC_INIT register.
Notes: • The CAS latency specified in the MRS command must be the same as the setting for
CAS[1:0]/SDRAMC_APP register.
• After the initial sequence commands are executed, the command enable bit must be set to 0.
Write 0x10 to the SDRAMC_INIT register after the last initialization command has been ex-
ecuted.
• The self-refresh function must be disabled until the SDRAM has finished initialization.
4. Checking if the SDRAM has been initialized
INIDO/SDRAMC_INIT register is reset to 0 after power-on, and is set to 1 upon completion of the SDRAM
initialization sequence shown above. Make sure that INIDO is set to 1 before the SDRAM is accessed.
In addition to being reset at power-on, INIDO is reset to 0 by writing 0 to SDON/SDRAMC_INIT register.
SDRAM power supply
SDCLK
Command
SDCKE
#SDCS
#SDRAS
#SDCAS
#SDWE
DQMH/DQML
SDON bit
INIPRE bit
INIREF bit
INIMRS bit
INIDO bit
SDA10
SDBA[1:0]
SDA[12:11, 9:0]
PALL
H
H
REF
REF
MRS
CMD
Valid
Valid
Valid
Valid
Valid
100
µ
s
(min.)
t
RP
t
RFC
t
RFC
V
CC(min.)
5.1.1 SDRAM Power-on and Initialization
Figure 10.