HD6412340 HITACHI [Hitachi Semiconductor], HD6412340 Datasheet - Page 116

• Manufacturer Part Number: HD6412340
• Description: H8S/2345 F-ZTAT Hardware Manual
• Manufacturer: HITACHI [Hitachi Semiconductor]

4.2.4
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
After reset release, MSTPCR is initialized to H'3FFF and all modules except the 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.
96
RES
Address bus
RD
HWR, LWR
D
(1) (3) Reset exception handling vector address ((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
Note: * 3 program wait states are inserted.
15
Interrupts after Reset
State of On-Chip Supporting Modules after Reset Release
to D
ø
0
Figure 4.3 Reset Sequence (Mode 4)
*
(1)
Vector fetch
(2)
High
*
(3)
Internal
processing
(4)
Prefetch of first
program instruction
(5)
*
(6)