h8s-2172 Renesas Electronics Corporation., h8s-2172 Datasheet - Page 138

• Manufacturer Part Number: h8s-2172
• Description: Renesas 16-bit Single-chip Microcomputer H8s Family H8s-2100 Series
• Manufacturer: Renesas Electronics Corporation.

Number of Access States: Two or three access states can be selected with ACSCR. An area for
which 2-state access is selected functions as a 2-state access space, and an area for which 3-state
access is selected functions as a 3-state access space. With the DRAM interface, the number of
access states may be determined without regard to the setting of ACSCR.
When 2-state access space is designated, wait insertion is disabled. When 3-state access space is
designated, it is possible to insert program waits by means of WTCR.
Number of Program Wait States: When 3-state access space is designated by ACSCR, the
number of program wait states to be inserted automatically is selected with WTCR. From 0 to 7
program wait states can be selected. Table 6.3 shows the bus specifications (bus width, and
number of access states and program wait states) for each basic bus interface area.
Table 6.3
Legend n = 3 to 0
Rev. 2.00, 03/04, page 106 of 534
ABWn
0
1
ACSCR
ASTn
0
1
0
1
Bus Specifications for Each Area (Basic Bus Interface)
Wn2

0
1

0
1
Wn1

0
1
0
1

0
1
0
1
WTCR
Wn0

0
1
0
1
0
1
0
1

0
1
0
1
0
1
0
1
Bus Width
16
8
Bus Specifications (Basic Bus Interface)
Access
States
2
3
2
3
Program Wait
States
0
0
1
2
3
4
5
6
7
0
0
1
2
3
4
5
6
7