mcf5272 Freescale Semiconductor, Inc, mcf5272 Datasheet - Page 137

• Manufacturer Part Number: mcf5272
• Description: Mcf5272 Coldfire Integrated Microprocessor User
• Manufacturer: Freescale Semiconductor, Inc

MOTOROLA
5.5 Background Debug Mode (BDM)
The ColdFire Family implements a low-level system debugger in the microprocessor
hardware. Communication with the development system is handled through a dedicated,
high-speed serial command interface. The ColdFire architecture implements the BDM
controller in a dedicated hardware module. 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.
5.5.1 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:
20–18/
Bits
21/5
20/4
19/3
18/2
17/1
16/0
4–2
1. A catastrophic fault-on-fault condition automatically halts the processor.
2. A hardware breakpoint can be configured to generate a pending halt condition
3. The execution of a HALT instruction immediately suspends execution. Attempting
similar to the assertion of BKPT. This type of halt is always first made pending in
the processor. Next, the processor samples for pending halt and interrupt conditions
once per instruction. When a pending condition is asserted, the processor halts
execution at the next sample point. See Section 5.6.1, “Theory of Operation.”
to execute HALT in user mode while CSR[UHE] = 0 generates a privilege violation
exception. If CSR[UHE] = 1, HALT can be executed in user mode. After HALT
executes, the processor can be restarted by serial shifting a
debug module. Execution continues at the instruction after HALT.
Name
EPC
EAx
PCI
DI
Data breakpoint invert. Provides a way to invert the logical sense of all the data breakpoint
comparators. This can develop a trigger based on the occurrence of a data value other than the
DBR contents.
Enable address bits. Setting an EA bit enables the corresponding address breakpoint. Clearing all
three bits disables the breakpoint.
EAI
EAR
EAL
Enable PC breakpoint. If set, this bit enables the PC breakpoint.
Breakpoint invert. If set, this bit allows execution outside a given region as defined by PBR and
PBMR to enable a trigger. If cleared, the PC breakpoint is defined within the region defined by PBR
and PBMR.
Table 5-14. TDR Field Descriptions (Continued)
Enable address breakpoint inverted. Breakpoint is based outside the range between
ABLR and ABHR.
Enable address breakpoint range. The breakpoint is based on the inclusive range defined
by ABLR and ABHR.
Enable address breakpoint low. The breakpoint is based on the address in the ABLR.
Chapter 5. Debug Support
Description
Background Debug Mode (BDM)
GO
command into the
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