HD6412320 RENESAS [Renesas Technology Corp], HD6412320 Datasheet - Page 179

• Manufacturer Part Number: HD6412320
• Description: Renesas 16-Bit Single-Chip Microcomputer H8S Family H8S-2300 Series
• Manufacturer: RENESAS [Renesas Technology Corp]

6.2
6.2.1
Modes 5 to 7
Mode 4
ABWCR is an 8-bit readable/writable register that designates each area for either 8-bit access or
16-bit access.
ABWCR sets the data bus width for the external memory space. The bus width for on-chip
memory and internal I/O registers is fixed regardless of the settings in ABWCR.
After a reset and in hardware standby mode, ABWCR is initialized to H'FF in modes 5 to 7, * and
to H'00 in mode 4. It is not initialized in software standby mode.
Note: * Modes 6 and 7 are not provided in the ROMless version.
Bits 7 to 0—Area 7 to 0 Bus Width Control (ABW7 to ABW0): These bits select whether the
corresponding area is to be designated for 8-bit access or 16-bit access.
Bit n
ABWn
0
1
Bit
Initial value :
R/W
Initial value :
R/W
Register Descriptions
Bus Width Control Register (ABWCR)
Description
Area n is designated for 16-bit access
Area n is designated for 8-bit access
:
:
:
ABW7
R/W
R/W
7
1
0
ABW6
R/W
R/W
6
1
0
ABW5
R/W
R/W
5
1
0
ABW4
R/W
R/W
4
1
0
Rev.6.00 Sep. 27, 2007 Page 149 of 1268
ABW3
R/W
R/W
3
1
0
ABW2
R/W
R/W
2
1
0
Section 6 Bus Controller
REJ09B0220-0600
ABW1
R/W
R/W
1
1
0
(n = 7 to 0)
ABW0
R/W
R/W
0
1
0