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SH7751 Group, SH7751R Group
Section 13 Bus State Controller (BSC)
R01UH0457EJ0301 Rev. 3.01
Page 357 of 1128
Sep 24, 2013
13.2.2
Bus Control Register 2 (BCR2)
Bus control register 2 (BCR2) is a 32-bit readable/writable register that specifies the bus width for
each area, and whether a 16-bit port is used.
BCR2 is initialized to H'3FFC by a power-on reset, but is not initialized by a manual reset or in
standby mode. External memory space other than area 0 should not be accessed until register
initialization is completed.
Bit:
15 14 13 12 11 10 9 8
A0SZ1 A0SZ0 A6SZ1 A6SZ0 A5SZ1 A5SZ0 A4SZ1 A4SZ0
Initial
value:
0/1
*
0/1
*
1 1 1 1 1 1
R/W: R
R R/W R/W R/W R/W R/W R/W
Bit:
7 6 5 4 3 2 1 0
A3SZ1 A3SZ0 A2SZ1 A2SZ0 A1SZ1 A0SZ0
— PORTEN
Initial
value:
1 1 1 1 1 1 0 0
R/W:
R/W R/W R/W R/W R/W R/W — R/W
Note:
*
These bits sample the values of the external pins that specify the area 0 bus size.
Bits 15 and 14—Area 0 Bus Width (A0SZ1, A0SZ0):
These bits sample the external pins (MD3
and MD4) that specify the bus size in a power-on reset. They are read-only bits.
Bit 15: MD4
Bit 14: MD3
Bus Width
0
0
Reserved (Setting prohibited)
1
8
bits
1 0 16
bits
1
32
bits