Renesas SH7781 Manual De Usuario
12. DDR2-SDRAM Interface (DBSC2)
Rev.1.00 Jan. 10, 2008 Page 512 of 1658
REJ09B0261-0100
REJ09B0261-0100
12.5
DBSC2 Operation
12.5.1
Supported SDRAM Commands
Table 12.11 lists the SDRAM commands issued by the DBSC2. These commands are issued to the
DDR2-SDRAM in synchronously with MCK0,
DDR2-SDRAM in synchronously with MCK0,
MCK0, MCK1, and MCK1. In the table, n-1
indicates the state of the signal applied to DDR2-SDRAM one cycle before SDRAM command
issue; n indicates the state of the signal at the time of command issue.
issue; n indicates the state of the signal at the time of command issue.
Table 12.11 SDRAM Commands Issued by the DBSC2
MCKE
Function Symbol
n-1
n
MCS MRAS MCAS MWE
MA
[14:11]
[14:11]
MA10/
AP
AP
MBA
[2:0]
[2:0]
MA
[9:0]
[9:0]
Device
deslect
deslect
DSEL
H
H
H
X X X
X X X X
Read READ
H
H
L
H
L
H
V
L
V
V
Write
WRITE
H
H
L H L L V L V V
Bank
activate
ACT
H
H
L L H H
V V V V
Precharge
select bank
select bank
PRE H
H
L L H L X L V X
Precharge all
banks
banks
PALL
H
H
L L H L X H X X
Auto-
refresh
refresh
REF
H
H
L L L H
X X X X
Self-
refresh entry
from IDLE
refresh entry
from IDLE
SLFRSH
H
L
L L L H
X X X X
Self-
refresh exit
refresh exit
SLFRSHX
L
H
H
X X X
X X X X
Mode register
set
set
MRS/
EMRS
EMRS
H
H
L L L L V V V V
Legend:
H: High level
L: Low level
X: High or low level (don't care)
V: Valid data
The above DSEL command is issued when DDR2-SDRAM is not accessed, and so need not be
explicitly issued by the user.
explicitly issued by the user.