HD6433044 Hitachi Semiconductor, HD6433044 Datasheet - Page 129

• Manufacturer Part Number: HD6433044
• Description: (HD64 Series) Hitachi Single-Chip Microcomputer
• Manufacturer: Hitachi Semiconductor

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.
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
0
1
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. These
settings are therefore meaningless in single-chip mode (mode 7).
Bit
Initial value
Read/Write
AST7
Description
Areas 7 to 0 are accessed in two states
Areas 7 to 0 are accessed in three states
R/W
7
1
AST6
Bits selecting number of states for access to each area
R/W
6
1
AST5
R/W
5
1
115
AST4
R/W
4
1
AST3
R/W
3
1
AST2
R/W
2
1
AST1
R/W
1
1
(Initial value)
AST0
R/W
0
1