Datasheet

Section 4 Exception Handling
Rev. 2.00 Sep. 28, 2009 Page 63 of 870
REJ09B0429-0200
Section 4 Exception Handling
4.1 Exception Handling Types and Priority
As table 4.1 indicates, exception handling may be caused by a reset, interrupt, illegal instruction,
or trap instruction. Exception handling is prioritized as shown in table 4.1. If two or more
exceptions occur simultaneously, they are accepted and processed in order of priority.
Table 4.1 Exception Types and Priority
Priority Exception Type Start of Exception Handling
High Reset Starts immediately after a low-to-high transition of the RES
pin, or when the watchdog timer overflows.
Illegal instruction Started by execution of an undefined code.
Interrupt Starts when execution of the current instruction or exception
handling ends, if an interrupt request has been issued.
Interrupt detection is not performed on completion of ANDC,
ORC, XORC, or LDC instruction execution, or on
completion of reset exception handling.
Low
Trap instruction Started by execution of a trap (TRAPA) instruction. Trap
instruction exception handling requests are accepted at all
times in program execution state.