655
19.3
Operation
When the RAME bit is set to 1, accesses to addresses H'FFE000 to H'FFEFBF and H'FFFFC0 to
H'FFFFFF in the H8S/2646, H8S/2646R, H8S/2648, and H8S/2648R to addresses H'FFE7C0 to
H'FFEFBF and H'FFFFC0 to H'FFFFFF in the H8S/2645 and H8S/2647, are directed to the on-
chip RAM. When the RAME bit is cleared to 0, the off-chip address space is accessed.
Since the on-chip RAM is connected to the CPU by an internal 16-bit data bus, it can be written to
and read in byte or word units. Each type of access can be performed in one state.
Even addresses use the upper 8 bits, and odd addresses use the lower 8 bits. Word data must start
at an even address.
19.4
Usage Notes
When Using the DTC: DTC register information can be located in addresses H'FFEBC0 to
H'FFEFBF. When the DTC is used, the RAME bit must not be cleared to 0.
Reserved Areas: Addresses H'FFB000 to H'FFDFFF in the H8S/2646, H8S/2646R, H8S/2648,
and H8S/2648R and addresses H'FFB000 to H'FFE7BF in the H8S/2645 and H8S/2647 are
reserved areas that cannot be read or written to. When the RAME bit is cleared to 0, the off-chip
address space is accessed.
Содержание H8S/2645
Страница 4: ......
Страница 16: ......
Страница 58: ...26 ...
Страница 110: ...78 ...
Страница 120: ...88 ...
Страница 132: ...100 ...
Страница 160: ...128 ...
Страница 172: ...140 ...
Страница 235: ...203 Transfer SAR or DAR DAR or SAR Block area First block Nth block Figure 8 8 Memory Mapping in Block Transfer Mode ...
Страница 418: ...386 ...
Страница 444: ...412 ...
Страница 530: ...498 ...
Страница 562: ...530 ...
Страница 642: ...610 ...
Страница 662: ...630 ...
Страница 688: ...656 ...
Страница 756: ...724 ...
Страница 784: ...752 ...
Страница 812: ...780 ...
Страница 837: ...805 A 2 Instruction Codes Table A 2 shows the instruction codes ...
Страница 1152: ...1120 ...