h8s-2172 Renesas Electronics Corporation., h8s-2172 Datasheet - Page 90

• Manufacturer Part Number: h8s-2172
• Description: Renesas 16-bit Single-chip Microcomputer H8s Family H8s-2100 Series
• Manufacturer: Renesas Electronics Corporation.

4.3.2
If an interrupt is accepted after a reset and 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 a reset is cancelled, the module stop control register (MSTPCR) is initialized, and all
modules except the DMAC operate in module stop mode. Therefore, the registers of on-chip
peripheral modules cannot be read from or written to. To read from and write to these registers,
clear module stop mode.
Rev. 2.00, 03/04, page 58 of 534
φ
RES
Internal address bus
Internal read signal
Internal write signal
Internal data bus
(1), (3)
(2), (4)
Interrupts after Reset
On-Chip Peripheral Modules after Reset is Cancelled
(5)
(6)
Reset exception handling vector address ((1) = H'000000, (3) = H'000002)
Start address (contents of reset exception handling vector address)
Start address ((5) = (2)(4))
First program instruction
Figure 4.1 Reset Sequence
(1)
(2)
Vector
fetch
High
(4)
processing
(3)
Internal
Prefetch of first program
instruction
(5)
(6)