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SH7751 Group, SH7751R Group
Section 13 Bus State Controller (BSC)
R01UH0457EJ0301 Rev. 3.01
Page 363 of 1128
Sep 24, 2013
13.2.5
Wait Control Register 1 (WCR1)
Wait control register 1 (WCR1) is a 32-bit readable/writable register that specifies the number of
idle state insertion cycles for each area. With some kinds of memory, data bus drive does not go
off immediately after the read signal from off-chip goes off. As a result, there is a possibility of a
data bus collision when consecutive memory accesses are performed on memory in different
areas, or when a memory write is performed immediately after a read. In this LSI, the number of
idle cycles set in the WCR1 register are inserted automatically if there is a possibility of this kind
of data bus collision.
WCR1 is initialized to H'77777777 by a power-on reset, but is not initialized by a manual reset or
in standby mode.
Bit:
31 30 29 28 27 26 25 24
— DMAIW2
DMAIW1 DMAIW0
—
A6IW2 A6IW1 A6IW0
Initial
value:
0 1 1 1 0 1 1 1
R/W: R R/W R/W R/W R R/W R/W R/W
Bit:
23 22 21 20 19 18 17 16
—
A5IW2 A5IW1 A5IW0
—
A4IW2 A4IW1 A4IW0
Initial
value:
0 1 1 1 0 1 1 1
R/W: R R/W R/W R/W R R/W R/W R/W
Bit:
15 14 13 12 11 10 9 8
—
A3IW2 A3IW1 A3IW0
—
A2IW2 A2IW1 A2IW0
Initial
value:
0 1 1 1 0 1 1 1
R/W: R R/W R/W R/W R R/W R/W R/W
Bit:
7 6 5 4 3 2 1 0
—
A1IW2 A1IW1 A1IW0
—
A0IW2 A0IW1 A0IW0
Initial
value:
0 1 1 1 0 1 1 1
R/W: R R/W R/W R/W R R/W R/W R/W
Bits 31, 27, 23, 19, 15, 11, 7, and 3—Reserved:
These bits are always read as 0, and the write
value should always be 0.