Datasheet

Section 7 Bus Controller
R01UH0166EJ0600 Rev. 6.00 Page 177 of 1434
Mar 02, 2011
H8S/2633 Group, H8S/2633 F-ZTAT
TM
,
H8S/2633R F-ZTAT
TM
, H8S/2695
7.2.2 Access State Control Register (ASTCR)
7
AST7
1
R/W
6
AST6
1
R/W
5
AST5
1
R/W
4
AST4
1
R/W
3
AST3
1
R/W
0
AST0
1
R/W
2
AST2
1
R/W
1
AST1
1
R/W
Bit
Initial value
R/W
:
:
:
ASTCR is an 8-bit readable/writable register that designates each area as either a 2-state access
space or a 3-state access space.
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.
In normal mode, the settings of bits AST7 to AST1 have no effect on operation.
ASTCR is initialized to H'FF by a power-on reset and in hardware standby mode. It is not
initialized by a manual reset or 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 (Initial value)
Wait state insertion in area n external space is enabled
(n = 7 to 0)