HD64F3028F25 Datasheet, PDF (107/925 Pages) Renesas Technology Corp – Hardware Manual Renesas 16-Bit Single-Chip Microcomputer H8 Family/H8/300H Series

Prefetch of
Internal
first program
Vector fetch processing instruction
φ
RES
Internal
address bus
Internal
read signal
Internal
write signal
Internal
data bus
(16 bits wide)
(1)
(2)
(2)
(3)
(1) Address of reset vector (H'0000)
(2) Start address (contents of reset exception handling vector address)
(3) First instruction of program
Figure 4.4 Reset Sequence (Mode 6)
4.2.3 Interrupts after Reset
If an interrupt is accepted after a reset but before the stack pointer (SP) is initialized, 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. The first instruction of the program is
always executed immediately after the reset state ends. This instruction should initialize the stack
pointer (example: MOV.L #xx:32, SP).
Rev. 2.00, 09/03, page 75 of 890