h8s-2158 Renesas Electronics Corporation., h8s-2158 Datasheet - Page 162

• Manufacturer Part Number: h8s-2158
• Description: Renesas 16-bit Single-chip Microcomputer H8s Family/h8s/2100 Series
• Manufacturer: Renesas Electronics Corporation.

Section 6 Bus Controller
6.3.3
WSCR is used to specify the data bus width for external address space access, the number of
access states, the wait mode, and the number of wait states for access to external address spaces
(basic expansion area and 256-kbyte expansion area). The bus width and the number of access
states for internal memory and internal I/O registers are fixed regardless of the WSCR settings.
Rev. 3.00 Jan 25, 2006 page 110 of 872
REJ09B0286-0300
Bit
7
6
5
Bit Name
ABW256
AST256
ABW
Wait State Control Register (WSCR)
Initial Value
1
1
1
R/W
R/W
R/W
R/W
256-kbyte Expansion Area Bus Width Control
Selects the bus width for access to the 256-kbyte
expansion area when the CS256E bit in SYSCR is set
to 1.
0: 16-bit bus
1: 8-bit bus
Selects the number of states for access to the 256-
kbyte expansion area when the CS256E bit in SYSCR
is set to 1. This bit also enables or disables wait-state
insertion.
0: 2-state access space. Wait state insertion disabled in
1: 3-state access space. Wait state insertion enabled in
Bus Width Control
Selects the bus width for access to the basic expansion
area.
0: 16-bit bus
1: 8-bit bus
When the CS256E bit in SYSCR and the CPCSE bit in
BCR2 are set to 1, this bit setting is ignored in 256-
kbyte expansion area access and CP/CF expansion
area access.
Description
256-kbyte Expansion Area Access State Control
256-kbyte expansion area access
256-kbyte expansion area access