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13.2.2
Bus Control Register 2 (BCR2)
Bus control register 2 (BCR2) is a 16-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:
Bit name:
Initial value:
R/W:
Bit:
Bit name:
Initial value:
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, MD4
and MD3 that specify the bus size in a power-on reset. They are read-only bits.
Bit15
A0SZ1
0
1
Rev. 4.0, 04/00, page 280 of 850
15
14
A0SZ1
A0SZ0
0/1*
0/1*
R
R
7
6
A3SZ1
A3SZ0
1
1
R/W
R/W
Bit14
A0SZ0
0
1
0
1
13
12
A6SZ1
A6SZ0
1
1
R/W
R/W
5
4
A2SZ1
A2SZ0
1
1
R/W
R/W
Description
Bus width is 64 bits
Bus width is 8 bits
Bus width is 16 bits
Bus width is 32 bits
11
10
A5SZ1
A5SZ0
1
1
R/W
R/W
3
2
A1SZ1
A0SZ0
1
1
R/W
R/W
9
8
A4SZ1
A4SZ0
1
1
R/W
R/W
1
0
—
PORTEN
0
0
—
R/W
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