Nios II Classic Processor Reference Guide

ID 683620
Date 10/28/2016
Document Table of Contents

3.7.5. Break Exceptions

A break is a transfer of control away from a program’s normal flow of execution for the purpose of debugging. Software debugging tools can take control of the Nios® II processor via the JTAG debug module.

Break processing is the means by which software debugging tools implement debug and diagnostic features, such as breakpoints and watchpoints. Break processing is a type of exception processing, but the break mechanism is independent from general exception processing. A break can occur during exception processing, enabling debug tools to debug exception handlers.

The processor enters the break processing state under either of the following conditions:

  • The processor executes the break instruction. This is often referred to as a software break.
  • The JTAG debug module asserts a hardware break.