mcf51ac256a Freescale Semiconductor, Inc, mcf51ac256a Datasheet - Page 83

• Manufacturer Part Number: mcf51ac256a
• Description: Mcf51ac Flexis
• Manufacturer: Freescale Semiconductor, Inc

Chapter 5
Resets, Interrupts, and General System Control
5.1
This chapter discusses basic reset and interrupt mechanisms and the various sources of reset and interrupt
on MCF51AC256 series microcontrollers. Some interrupt sources from peripheral modules are discussed
in greater detail within other sections of this document. This chapter gathers basic information about all
reset and interrupt sources in one place for easy reference. A few reset and interrupt sources, including the
computer operating properly (COP) watchdog are not part of on-chip peripheral systems with their own
chapters.
5.2
Reset and interrupt features include:
5.3
Resetting the microcontroller provides a way to start processing from an known set of initial conditions.
When the ColdFire processor exits reset, it fetches initial 32-bit values for the supervisor stack pointer and
program counter from locations 0x(00)00_0000 and 0x(00)00_0004 respectively. On-chip peripheral
modules are disabled and I/O pins are initially configured as general-purpose high-impedance inputs with
pullup devices disabled.
The MCF51AC256 series microcontrollers have the following sources for reset:
Each of these sources, with the exception of the background debug forced reset, has an associated bit in
the system reset status register (SRS).
Freescale Semiconductor
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Multiple sources of reset for flexible system configuration and reliable operation
System reset status (SRS) register to indicate source of most recent reset
Separate interrupt vector for most modules (reduces polling overhead) (see
Power-on reset (POR)
External pin reset (PIN)
Computer operating properly (COP) timer
Illegal opcode detect (ILOP)
Illegal address detect (ILAD)
Low-voltage detect (LVD)
Clock generator (MCG) loss of clock reset (LOC)
Background debug forced reset
Introduction
Features
Microcontroller Reset
MCF51AC256 ColdFire Integrated Microcontroller Reference Manual, Rev. 5
Table
5-1)
5-1