
Technical Data
MC68HC11E Family
—
Rev. 4
108
Resets and Interrupts
MOTOROLA
Resets and Interrupts
5.7
5.7.1
5.7.2
Low-Power Operation. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .129
Wait Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .130
Stop Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .130
5.2 Introduction
Resets and interrupt operations load the program counter with a vector
that points to a new location from which instructions are to be fetched. A
reset immediately stops execution of the current instruction and forces
the program counter to a known starting address. Internal registers and
control bits are initialized so the MCU can resume executing instructions.
An interrupt temporarily suspends normal program execution while an
interrupt service routine is being executed. After an interrupt has been
serviced, the main program resumes as if there had been no
interruption.
5.3 Resets
The four possible sources of reset are:
Power-on reset (POR)
External reset (RESET)
Computer operating properly (COP) reset
Clock monitor reset
POR and RESET share the normal reset vector. COP reset and the
clock monitor reset each has its own vector.