85
ø
RES
,
MRES
Internal
address bus
Internal read
signal
Internal write
signal
Internal data
bus
Vector
fetch
(1)
(3)
(5)
High
Internal
processing
Prefetch of
first program
instruction
(2)
(4)
(1) (3) Reset exception handling vector address (when power-on reset, (1) = H'000000,
(3) = H'000002)
(2) (4) Start address (contents of reset exception handling vector address)
(5)
Start address ((5) = (2) (4))
(6)
First program instruction
(6)
Figure 4-3 Reset Sequence (Modes 6 and 7)
4.2.4
Interrupts after Reset
If an interrupt is accepted after a reset but before the stack pointer (SP) is initialized, the PC and
CCR will not be saved correctly, leading to a program crash. To prevent this, all interrupt requests,
including NMI, are disabled immediately after a reset. Since the first instruction of a program is
always executed immediately after the reset state ends, make sure that this instruction initializes
the stack pointer (example: MOV.L #xx: 32, SP).
4.2.5
State of On-Chip Supporting Modules after Reset Release
After reset release, MSTPCRA to MSTPCRC are initialized to H'3F, H'FF, and H'FF, respectively,
and all modules except the DMAC and DTC, enter module stop mode. Consequently, on-chip
supporting module registers cannot be read or written to. Register reading and writing is enabled
when module stop mode is exited.
Содержание H8S/2631
Страница 28: ...xviii Appendix G Package Dimensions 1154 ...
Страница 341: ...316 Transfer SAR or DAR DAR or SAR Block area First block Nth block Figure 9 8 Memory Mapping in Block Transfer Mode ...
Страница 918: ...905 ø DREQ0 DREQ1 tDRQS tDRQH Figure 25 19 DMAC DREQ Input Timing ...
Страница 955: ...943 A 2 Instruction Codes Table A 2 shows the instruction codes ...