Rev. 3.0, 10/02, page 111 of 686
6.4.2
Bus Specifications
The external space bus specifications consist of three elements: bus width, number of access states,
and number of program wait states.
The bus width and number of access states for on-chip memory and internal I/O registers except
for the on-chip USB are fixed, and are not affected by the bus controller.
(1) Bus Width: A bus width of 8 or 16 bits can be selected with ABWCR. An area for which an 8-
bit bus is selected functions as an 8-bit access space, and an area for which a 16-bit bus is
selected functions as a 16-bit access space.
If all areas are designated for 8-bit access, 8-bit bus mode is set; if any area is designated for
16-bit access, 16-bit bus mode is set. When the burst ROM interface is designated, 16-bit bus
mode is always set. 8-bit bus mode should be set for area 6 in this LSI.
(2) Number of Access States: Two or three access states can be selected with ASTCR.
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 burst ROM interface, the number of access states may be determined without regard
to ASTCR.
When 2-state access space is designated, wait insertion is disabled.
Area 6 should be set to function as a 3-state access space in this LSI.
(3) Number of Program Wait States: When 3-state access space is designated by ASTCR, the
number of program wait states to be inserted automatically is selected with WCRH and
WCRL.
From 0 to 3 program wait states can be selected.
The number of program wait states in area 6 should be set to 0 in this LSI.
Содержание H8S/2215 Series
Страница 4: ...Rev 3 0 10 02 page iv of lviii ...
Страница 6: ...Rev 3 0 10 02 page vi of lviii ...
Страница 28: ...Rev 3 0 10 02 page xxviii of lviii ...
Страница 122: ...Rev 3 0 10 02 page 64 of 686 ...
Страница 132: ...Rev 3 0 10 02 page 74 of 686 ...
Страница 156: ...Rev 3 0 10 02 page 98 of 686 ...
Страница 198: ...Rev 3 0 10 02 page 140 of 686 ...
Страница 320: ...Rev 3 0 10 02 page 262 of 686 ...
Страница 384: ...Rev 3 0 10 02 page 326 of 686 ...
Страница 474: ...Rev 3 0 10 02 page 416 of 686 ...
Страница 481: ...Rev 3 0 10 02 page 423 of 686 I O pin Control OUT IN TDI pin TDO pin Figure 14 2 Boundary Scan Register Configuration ...
Страница 608: ...Rev 3 0 10 02 page 550 of 686 ...
Страница 614: ...Rev 3 0 10 02 page 556 of 686 ...
Страница 650: ...Rev 3 0 10 02 page 592 of 686 ...
Страница 652: ...Rev 3 0 10 02 page 594 of 686 ...
Страница 680: ...Rev 3 0 10 02 page 622 of 686 ...
Страница 721: ...Rev 3 0 10 02 page 663 of 686 ø A23 to A0 to tBRQS tBACD tBZD tBACD tBZD tBRQS Figure 24 11 External Bus Release Timing ...
Страница 732: ...Rev 3 0 10 02 page 674 of 686 ...
Страница 740: ...Rev 3 0 10 02 page 682 of 686 ...