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Debug Module
MCF52211 ColdFire® Integrated Microcontroller Reference Manual, Rev. 2
28-34 Freescale Semiconductor
Operand Data: None
Result Data: The command-complete response (0xFFFF) is returned during the next shift
operation.
28.5.3.3.8 No Operation (NOP)
NOP performs no operation and may be used as a null command where required.
Command Formats:
Command Sequence:
Figure 28-33. NOP Command Sequence
Operand Data: None
Result Data: The command-complete response, 0xFFFF (with S cleared), is returned during the
next shift operation.
28.5.3.3.9 Synchronize PC to the PST/DDATA Lines (SYNC_PC)
The SYNC_PC command captures the current PC and displays it on the PST/DDATA outputs. After the
debug module receives the command, it sends a signal to the ColdFire processor that the current PC must
be displayed. The processor then forces an instruction fetch at the next PC with the address being captured
in the DDATA logic under control of the CSR[BTB] bits. The specific sequence of PST and DDATA
values is defined below:
1. Debug signals a
SYNC_PC command is pending.
2. CPU completes the current instruction.
3. CPU forces an instruction fetch to the next PC, generates a PST equaling 0x5 value indicating a
taken branch and signals the capture of DDATA.
4. The instruction address corresponding to the PC is captured.
5. The PST marker (0x9–0xB) is generated and displayed as defined by the CSR[BTB] bit followed
by the captured PC address.
The
SYNC_PC command can be used to dynamically access the PC for performance monitoring. The
execution of this command is considerably less obtrusive to the real-time operation of an application than
a HALT-CPU/READ-PC/RESUME command sequence.
Command Formats:
1514131211109876543210
0x00x00x00x0
Figure 28-32. NOP Command Format
NOP
???
NEXT CMD
’CMD COMPLETE’