MC68HC908GZ8 FREESCALE [Freescale Semiconductor, Inc], MC68HC908GZ8 Datasheet - Page 169

• Manufacturer Part Number: MC68HC908GZ8
• Description: M68HC08 Microcontrollers
• Manufacturer: FREESCALE [Freescale Semiconductor, Inc]

Chapter 14
Resets and Interrupts
14.1 Introduction
Resets and interrupts are responses to exceptional events during program execution. A reset re-initializes
the microcontroller (MCU) to its startup condition. An interrupt vectors the program counter to a service
routine.
14.2 Resets
A reset immediately returns the MCU to a known startup condition and begins program execution from a
user-defined memory location.
14.2.1 Effects
A reset:
14.2.2 External Reset
A logic 0 applied to the RST pin for a time, t
PIN bit in the system integration module (SIM) reset status register.
14.2.3 Internal Reset
Sources:
All internal reset sources pull the RST pin low for 32 CGMXCLK cycles to allow resetting of external
devices. The MCU is held in reset for an additional 32 CGMXCLK cycles after releasing the RST pin.
Freescale Semiconductor
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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
Power-on reset (POR)
Computer operating properly (COP)
Low-power reset circuits
Illegal opcode
Illegal address
MC68HC908GZ16 • MC68HC908GZ8 Data Sheet, Rev. 4
RL
, generates an external reset. An external reset sets the
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