![Freescale Semiconductor MCF54455 Reference Manual Download Page 868](http://html1.mh-extra.com/html/freescale-semiconductor/mcf54455/mcf54455_reference-manual_2330541868.webp)
Debug Module
Freescale Semiconductor
34-26
then if
(PC_breakpoint)
if
(Address1_breakpoint
{&& Data1_breakpoint})
then if
(PC_breakpoint)
if
(Address_breakpoint
{&& Data_breakpoint})
then if
(PC_breakpoint
||
Address1_breakpoint{&& Data1_breakpoint})
if
(Address1_breakpoint
{&& Data1_breakpoint})
then if
(PC_breakpoint|| Address_breakpoint{&& Data_breakpoint})
In this example, PC_breakpoint is the logical summation of the PBR0/PBMR, PBR1, PBR2, and PBR3
breakpoint registers; Address_breakpoint is a function of ABHR, ABLR, and AATR; Data_breakpoint is
a function of DBR and DBMR; Address1_breakpoint is a function of ABHR1, ABLR1, and AATR1; and
Data1_breakpoint is a function of DBR1 and DBMR1. In all cases, the data breakpoints can be included
with an address breakpoint to further qualify a trigger event as an option.
34.4
Functional Description
34.4.1
Background Debug Mode (BDM)
The ColdFire family implements a low-level system debugger in the microprocessor in a dedicated
hardware module. Communication with the development system is managed through a dedicated,
high-speed serial command interface. Although some BDM operations, such as CPU register accesses,
require the CPU to be halted, other BDM commands, such as memory accesses, can be executed while the
processor is running.
BDM is useful because:
•
In-circuit emulation is not needed, so physical and electrical characteristics of the system are not
affected.
•
BDM is always available for debugging the system and provides a communication link for
upgrading firmware in existing systems.
•
Provides high-speed cache downloading (500 Kbytes/sec), especially useful for flash
programming
•
Provides absolute control of the processor, and thus the system. This allows quick hardware
debugging with the same tool set used for firmware development.
34.4.1.1
CPU Halt
Although most BDM operations can occur in parallel with CPU operations, unrestricted BDM operation
requires the CPU to be halted. The sources that can cause the CPU to halt are listed below in order of
priority:
1. A catastrophic fault-on-fault condition automatically halts the processor.
Summary of Contents for MCF54455
Page 33: ...xxviii Freescale Semiconductor ...
Page 67: ...Freescale Semiconductor 1 ...
Page 125: ...Freescale Semiconductor 1 ...
Page 145: ...Enhanced Multiply Accumulate Unit EMAC 5 21 Freescale Semiconductor ...
Page 173: ...Cache 6 28 Freescale Semiconductor ...
Page 179: ...Static RAM SRAM 7 6 Freescale Semiconductor ...
Page 207: ...Power Management 9 16 Freescale Semiconductor ...
Page 323: ...Reset Controller Module 13 8 Freescale Semiconductor ...
Page 389: ...Pin Multiplexing and Control 16 44 Freescale Semiconductor ...
Page 575: ...PCI Bus Controller 22 58 Freescale Semiconductor ...
Page 600: ...Advanced Technology Attachment ATA Freescale Semiconductor 23 25 ...
Page 601: ...Freescale Semiconductor 1 ...
Page 842: ...I2 C Interface Freescale Semiconductor 33 16 ...
Page 843: ...Freescale Semiconductor 1 ...
Page 921: ...Revision History A 6 Freescale Semiconductor ...