Datasheet

Section 3 Exception Handling
Page 70 of 982 REJ09B0465-0300 Rev. 3.00
Sep 17, 2010
H8S/20103, H8S/20203, H8S/20223, H8S/20115, H8S/20215, H8S/20235 Group
3.3.3 Interrupts immediately 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).
3.3.4 On-Chip Peripheral Functions after Reset Release
After release from a reset, MSTCR is initialized, and the DTC and all modules other than timer
RE enter module standby mode.
Consequently, on-chip peripheral module registers cannot be read or written to. Register reading
and writing is enabled when module standby mode is exited.