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Chapter 31 External Bus
2.External Bus Interface Registers
The following explains the function of each bit:
[Bits 15-12] ASZ3-0 (Area Size Bits 3-0)
These bits set the area size. Table 2-1 "Area Size Settings" shows their settings.
Table 2-1 Area Size Settings
ASZ3 ASZ2 ASZ1 ASZ0 Size of each chip select area
0 0 0 0 64 KB (00010000H byte, ASR A[31:16] bits are valid)
0 0 0 1 128 KB (00020000H byte, ASR A[31:17] bits are valid)
0 0 1 0 256 KB (00040000H byte, ASR A[31:18] bits are valid)
0 0 1 1 512 KB (00080000H byte, ASR A[31:19] bits are valid)
0 1 0 0 1 MB (00100000H byte, ASR A[31:20] bits are valid)
0 1 0 1 2 MB (00200000H byte, ASR A[31:21] bits are valid)
0 1 1 0 4 MB (00400000H byte, ASR A[31:22] bits are valid)
ACR4H 15 14 13 12 11 10 9 8
15 14 13 12 11 10 9 8
15 14 13 12 11 10 9 8
15 14 13 12 11 10 9 8
0000 0652HASZ3 ASZ2 ASZ1 ASZ0 DBW1DBW0 BST1 BST0
ACR4L
ACR5H
ACR5L
ACR6H
ACR6L
ACR7H
ACR7L
76543210
0000 0653HSREN PFEN WRENLEND TYP3 TYP2 TYP1 TYP0
0000 0656HASZ3 ASZ2 ASZ1 ASZ0 DBW1DBW0 BST1 BST0
76543210
0000 0657HSRENPFEN WRENLEND TYP3 TYP2 TYP1 TYP0
0000 065AHASZ3 ASZ2 ASZ1 ASZ0 DBW1 DBW0 BST1 BST0
76543210
0000 065BHSRENPFEN WRENLEND TYP3 TYP2 TYP1 TYP0
SREN PFEN WREN LEND TYP3 TYP2 TYP1 TYP0
0000 065EHASZ3 ASZ2 ASZ1 ASZ0 DBW1DBW0 BST1 BST0
76543210
0000 065FH
xxxxxxxxB xxxxxxxxBW/R
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W/R
W/R
W/R
W/R
W/R
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xxxxxxxxBxxxxxxxxB
W/R
W/R
Initial value
INIT RST Access