Chapter 29

Debug Support

This chapter describes the Revision A enhanced hardware debug support in the MCF5282.

29.1 Overview

The debug module is shown in Figure 29-1.

ColdFire CPU Core

Debug Module

 

 

Trace Port

 

 

 

 

Communication Port

Control

BKPT

PST[3:0], DDATA[3:0]

DSCLK, DSI, DSO

 

 

CLKOUT

 

 

High-speed local bus

Figure 29-1. Processor/Debug Module Interface

Debug support is divided into three areas:

Real-time trace support—The ability to determine the dynamic execution path through an application is fundamental for debugging. The ColdFire solution implements an 8-bit parallel output bus that reports processor execution status and data to an external emulator system. See Section 29.3, “Real-Time Trace Support.”

Background debug mode (BDM)—Provides low-level debugging in the ColdFire processor complex. In BDM, the processor complex is halted and a variety of commands can be sent to the processor to access memory and registers. The external emulator uses a three-pin, serial, full-duplex channel. See Section 29.5, “Background Debug Mode (BDM),” and Section 29.4, “Programming Model.”

Real-time debug support—BDM requires the processor to be halted, which many real-time embedded applications cannot do. Debug interrupts let real-time systems execute a unique service routine that can quickly save the contents of key registers and variables and return the system to normal operation. External development

MOTOROLA

Chapter 29. Debug Support

29-1

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Motorola MCF5281, MCF5282 user manual Debug module is shown in Figure, Processor/Debug Module Interface