Motorola ColdFire MCF5281 - Manual (Page 619)

Freescale Semiconductor 30-1
Chapter 30
Debug Support
This chapter describes the Revision A enhanced hardware debug support.
30.1 Overview
The debug module is shown in Figure 30-1 .
Figure 30-1. 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 30.3, “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 30.5, “Background Debug Mode (BDM) ,” and Section 30.4,
“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 systems can access saved data because the hardware
supports concurrent operation of the processor and BDM-initiated commands. See
Section 30.6,
“Real-Time Debug Support .”
NOTE
Enabling Flash security disables BDM communications.
ColdFire CPU Core
Debug Module
High-speed
Communication Port
DSCLK, DSI, DSO
Control
BKPT
local bus
Trace Port
PST[3:0], DDATA[3:0]
CLKOUT
MCF5282 and MCF5216 ColdFire Microcontroller User’s Manual, Rev. 3