MC68HC908GP20 Datasheet, PDF (70/406 Pages) Freescale Semiconductor, Inc – M68HC08 Microcontrollers

4.2 Introduction
Resets and interrupts are responses to exceptional events during
program execution. A reset re-initializes the MCU to its startup condition.
An interrupt vectors the program counter to a service routine.
4.3 Resets
A reset immediately returns the MCU to a known startup condition and
begins program execution from a user-defined memory location.
4.3.1 Effects
A reset:
• Immediately stops the operation of the instruction being executed
• Initializes certain control and status bits
• Loads the program counter with a user-defined reset vector
address from locations $FFFE and $FFFF
• Selects CGMXCLK divided by four as the bus clock
4.3.2 External Reset
A logic 0 applied to the RST pin for a time, t_IRL, generates an external
reset. An external reset sets the PIN bit in the SIM reset status register.
Advance Information
70
MC68HC908GP20 — Rev 2.1
Freescale Semiconductor