r4f2426 Renesas Electronics Corporation., r4f2426 Datasheet - Page 124

• Manufacturer Part Number: r4f2426
• Description: 16-bit Single-chip Microcomputer H8s Family / H8s/2400 Series
• Manufacturer: Renesas Electronics Corporation.

Section 4 Exception Handling
4.3.2
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).
4.3.3
After reset release, MSTPCR is initialized to H'0FFF, EXMSTPCR is initialized to H'FFFF, and
all modules except the DMAC, EXDMAC, and DTC enter module stop mode.
Consequently, on-chip peripheral module registers cannot be read or written to. Register reading
and writing is enabled when module stop mode is exited.
Rev. 1.00 Sep. 19, 2008 Page 96 of 1270
REJ09B0466-0100
(1)(3) Reset exception handling vector address (when 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
Note: * Seven program wait states are inserted.
RES
RD
HWR, LWR
D15 to D0
Figure 4.2 Reset Sequence (Advanced Mode with On-chip ROM Disabled)
φ
Address bus
Interrupts after Reset
On-Chip Peripheral Functions after Reset Release
(1)
*
Vector fetch
(2)
High
*
(3)
(4)
Internal
processing
Prefetch of first
program instruction
*
(5)
(6)