r4f2426 Renesas Electronics Corporation., r4f2426 Datasheet - Page 180

• Manufacturer Part Number: r4f2426
• Description: 16-bit Single-chip Microcomputer H8s Family / H8s/2400 Series
• Manufacturer: Renesas Electronics Corporation.

Section 6 Bus Controller (BSC)
6.3.1
ABWCR designates each area in the external address space as either 8-bit access space or 16-bit
access space.
Note:
6.3.2
ASTCR designates each area in the external address space as either 2-state access space or 3-state
access space.
Rev. 1.00 Sep. 19, 2008 Page 152 of 1270
REJ09B0466-0100
Bit
7
6
5
4
3
2
1
0
Bit
7
6
5
4
3
2
1
0
*
Bit Name
ABW7
ABW6
ABW5
ABW4
ABW3
ABW2
ABW1
ABW0
Bit Name
AST7
AST6
AST5
AST4
AST3
AST2
AST1
AST0
Bus Width Control Register (ABWCR)
Access State Control Register (ASTCR)
In modes 2 and 4, ABWCR is initialized to 1. In modes 1 and 7, ABWCR is initialized
to 0.
Initial Value*
1/0
1/0
1/0
1/0
1/0
1/0
1/0
1/0
Initial Value
1
1
1
1
1
1
1
1
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
Description
Area 7 to 0 Bus Width Control
These bits select whether the corresponding
area is to be designated as 8-bit access space
or 16-bit access space.
0: Area n is designated as 16-bit access space
1: Area n is designated as 8-bit access space
Description
Area 7 to 0 Access State Control
These bits select whether the corresponding
area is to be designated as 2-state access
space or 3-state access space. Wait state
insertion is enabled or disabled at the same
time.
0: Area n is designated as 2-state access
1: Area n is designated as 3-state access
(n = 7 to 0)
space
Wait state insertion in area n access is
disabled
space
Wait state insertion in area n access is
enabled
(n = 7 to 0)