MC68HC908AS60ACFN FREESCALE [Freescale Semiconductor, Inc], MC68HC908AS60ACFN Datasheet - Page 149

• Manufacturer Part Number: MC68HC908AS60ACFN
• Description: M68HC08 Microcontrollers
• Manufacturer: FREESCALE [Freescale Semiconductor, Inc]

Chapter 13
Break Module (BRK)
13.1 Introduction
The break module can generate a break interrupt that stops normal program flow at a defined address to
enter a background program.
13.2 Features
13.3 Functional Description
When the internal address bus matches the value written in the break address registers, the break module
issues a breakpoint signal to the CPU. The CPU then loads the instruction register with a software
interrupt instruction (SWI) after completion of the current CPU instruction. The program counter vectors
to $FFFC and $FFFD ($FEFC and $FEFD in monitor mode).
The following events can cause a break interrupt to occur:
When a CPU-generated address matches the contents of the break address registers, the break interrupt
begins after the CPU completes its current instruction. A return-from-interrupt instruction (RTI) in the
break routine ends the break interrupt and returns the MCU to normal operation.
structure of the break module.
Freescale Semiconductor
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Accessible I/O Registers during Break Interrupts
CPU-Generated Break Interrupts
Software-Generated Break Interrupts
COP Disabling during Break Interrupts
A CPU-generated address (the address in the program counter) matches the contents of the break
address registers.
Software writes a 1 to the BRKA bit in the break status and control register.
MC68HC908AZ60A • MC68HC908AS60A • MC68HC908AS60E Data Sheet, Rev. 6
Figure 13-1
shows the
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