Renesas R5S72621 User Manual
Section 9 Bus State Controller
Page 288 of 2108
R01UH0134EJ0400 Rev. 4.00
Sep
24,
2014
SH7262 Group, SH7264 Group
9.4.8
AC Characteristics Switching Register (ACSWR)
To use the SDRAM, set the AC characteristics switching register (ACSWR) and AC
characteristics key switching register (ACKEYR).
characteristics key switching register (ACKEYR).
Only a special sequence can write to this register to prevent accidental erroneous write. The
setting procedure is shown in section 9.4.10, Sequence to Write to ACSWR. Read is done by the
normal longword.
setting procedure is shown in section 9.4.10, Sequence to Write to ACSWR. Read is done by the
normal longword.
31
30
29
28
27
26
25
24
23
22
21
20
19
18
17
16
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
R
R
R
R
R
R
R
R
R
R
R
R
R
R
R
R
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
R
R
R
R
R
R
R
R
R
R
R
R
R/W
R/W
R/W
R/W
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
ACOSW[3:0]
Bit:
Initial value:
R/W:
Bit:
Initial value:
R/W:
Bit Bit
Name
Initial
Value R/W
Value R/W
Description
31 to 4
All
0
R
Reserved
These bits are always read as 0. The write value
should always be 0.
should always be 0.
3 to 0
ACOSW[3:0] 0000
R/W
AC Characteristics Switch
Specifies AC characteristics switching
0000: Not extend the delay time
0010: Switches characteristics and extends the delay
time
Others: Setting prohibited