Integrated Microcontroller Reference Manual

Debug Module
MCF52211 ColdFire® Integrated Microcontroller Reference Manual, Rev. 2
Freescale Semiconductor 28-39
Command Format:
Table 28-4 shows the definition of the DRc write encoding.
Command Sequence:
Figure 28-43. WDMREG Command Sequence
Operand Data: Longword data is written into the specified debug register. The data is supplied
most-significant word first.
Result Data: Command complete status (0xFFFF) is returned when register write is complete.
28.6 Real-Time Debug Support
The ColdFire family provides support debugging real-time applications. For these types of embedded
systems, the processor must continue to operate during debug. The foundation of this area of debug support
is that while the processor cannot be halted to allow debugging, the system can generally tolerate the small
intrusions of the BDM inserting instructions into the pipeline with minimal effect on real-time operation.
The debug module provides four types of breakpoints: PC with mask, PC without mask, operand address
range, and data with mask. These breakpoints can be configured into one- or two-level triggers with the
exact trigger response also programmable. The debug module programming model can be written from the
external development system using the debug serial interface or from the processor’s supervisor
programming model using the WDEBUG instruction. Only CSR is readable using the external
development system.
28.6.1 Theory of Operation
Breakpoint hardware can be configured through TDR[TCR] to respond to triggers by displaying DDATA,
initiating a processor halt, or generating a debug interrupt. As shown in Table 28-24, when a breakpoint is
triggered, an indication (CSR[BSTAT]) is provided on the DDATA output port when it is not displaying
captured processor status, operands, or branch addresses.
Figure 28-42. WDMREG BDM Command Format
1514131211109876543210
0x2 0xC 100 DRc
D[31:16]
D[15:0]
WDMREG
???
MS DATA
’NOT READY’
LS DATA
’NOT READY’
XXX
’ILLEGAL’
NEXT CMD
’NOT READY’
NEXT CMD
’CMD COMPLETE’