Version 1 ColdFire Debug (CF1_DEBUG)
MCF51CN128 Reference Manual
,
Rev. 6
20-2
Freescale Semiconductor
Figure 20-1. Simplified Version 1 ColdFire Core Block Diagram
20.1.1
Overview
Debug support is divided into three areas:
•
Background debug mode (BDM)—Provides low-level debugging in the ColdFire processor core.
In BDM, the processor core is halted and a variety of commands can be sent to the processor to
access memory, registers, and peripherals. The external emulator uses a one-pin serial
communication protocol. See
Section 20.4.1, “Background Debug Mode (BDM)”.
•
Real-time debug support—Use of the full BDM command set requires the processor to be halted,
which many real-time embedded applications cannot support. The core includes a variety of
internal breakpoint registers which can be configured to trigger and generate a special interrupt.
The resulting debug interrupt lets 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.
The external development system can then access the saved data, because the hardware supports
Central Processing Unit
Debug
Version 1 ColdFire Core (CF1Core)
IFP
OEP
BDC
CFx
BDM
PST/
DDATA
RTD
addr
rdata
wdata
BKGD
RESET
IPL_B[2:0]
IFP
— Instruction fetch pipeline
OEP
— Operand execution pipeline
BDC
— Background debug controller
CFxBDM
— ColdFire background debug module
PST/DDATA
— Processor status/debug data
RTD
— Real-time debug
(CF1Cpu)
(CF1Dbg)
attb
