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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).
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.
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
0000000000000000
RRRRRRRRRRRRRRRR
0000000000000000
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 Description
31 to 4 All 0 R Reserved
These bits are always read as 0. The write value
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