p2125vps20 Renesas Electronics Corporation., p2125vps20 Datasheet - Page 148

• Manufacturer Part Number: p2125vps20
• Description: 16-bit Single-chip Microcomputer H8s Family / H8s/2100 Series
• Manufacturer: Renesas Electronics Corporation.

Section 6 Bus Controller (BSC)
6.4
6.4.1
The external address space bus specifications consist of three elements: Bus width, the number of
access states, and the wait mode and the number of program wait states. The bus width and the
number of access states for on-chip memory and internal I/O registers are fixed, and are not
affected by the bus controller settings.
(1)
A bus width of 8 or 16 bits can be selected via the ABW bit in WSCR. However, 16-bit access
space cannot be selected in this LSI.
(2)
Two or three access states can be selected via the AST bit in WSCR. When the 2-state access
space is designated, wait-state insertion is disabled.
In the burst ROM interface, the number of access states is determined regardless of the AST bit
setting.
(3)
When a 3-state access space is designated by the AST bit in WSCR, the wait mode and the
number of program wait states to be inserted automatically is selected by the WMS1, WMS0,
WC1, and WC0 bits in WSCR. From 0 to 3 program wait states can be selected.
Rev. 1.00 Sep. 21, 2006 Page 110 of 658
REJ09B0310-0100
Bus Width
Number of Access States
Wait Mode and Number of Program Wait States
Bus Control
Bus Specifications