Hitachi H8S/2646 Hardware Manual page 177

ASTCR sets the number of access states for the external memory space. The number of access
states for on-chip memory and internal I/O registers is fixed regardless of the settings in ASTCR.
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 to be designated as a 2-state access space or a 3-state access space.
Wait state insertion is enabled or disabled at the same time.
Bit n
ASTn Description
0 Area n is designated for 2-state access
Wait state insertion in area n external space is disabled
1 Area n is designated for 3-state access
Wait state insertion in area n external space is enabled
(Initial value)
(n = 7 to 0)
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