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103
Bits 7 to 0—Area 7 to 0 Bus Width Control (ABW7 to ABW0): These bits select 8-bit access or
16-bit access for the corresponding areas.
Bits 7 to 0
ABW7 to ABW0
Description
0
Areas 7 to 0 are 16-bit access areas
1
Areas 7 to 0 are 8-bit access areas
ABWCR specifies the data bus width of external memory areas. The data bus width of on-chip
memory and registers is fixed, and does not depend on ABWCR settings.
6.2.2
Access State Control Register (ASTCR)
ASTCR is an 8-bit readable/writable register that selects whether each area is accessed in two
states or three states.
AST3
AST2
AST1
AST0
1
Initial value
1
1
1
1
1
1
1
Read/Write
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
7
6
5
4
3
2
1
0
Bits selecting number of states for access to each area
AST7
AST6
AST5
AST4
Bit
ASTCR is initialized to H'FF by a reset and in hardware standby mode. It is not initialized in
software standby mode.
Bits 7 to 0—Area 7 to 0 Access State Control (AST7 to AST0): These bits select whether the
corresponding area is accessed in two or three states.
Bits 7 to 0
AST7 to AST0
Description
0
Areas 7 to 0 are accessed in two states
1
Areas 7 to 0 are accessed in three states
(Initial value)
ASTCR specifies the number of states in which external areas are accessed. On-chip memory and
registers are accessed in a fixed number of states that does not depend on ASTCR settings.
Summary of Contents for H8/3008
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