mc9s12e256 Freescale Semiconductor, Inc, mc9s12e256 Datasheet - Page 499

• Manufacturer Part Number: mc9s12e256
• Description: Hcs12 Microcontrollers 16-bit Microcontroller
• Manufacturer: Freescale Semiconductor, Inc

16.4.3.2
A breakpoint request to the CPU can be created if BKCEN in DBGC2 is set. Breakpoints based on a
successful comparator C match can be accomplished regardless of the mode of operation for comparator
A or B, and do not affect the status of the ARM bit. TAGC in DBGC2 is used to select either tagged or
forced breakpoint requests for comparator C. Breakpoints based on comparator C are disabled in LOOP1
mode.
16.5
The DBG module is disabled after reset.
The DBG module cannot cause a MCU reset.
16.6
The DBG contains one interrupt source. If a breakpoint is requested and BDM in DBGC2 is cleared, an
SWI interrupt will be generated.
Freescale Semiconductor
BEGIN
Resets
Interrupts
0
0
0
0
1
1
1
1
Breakpoint Based on Comparator C
Because breakpoints cannot be disabled when the DBG is armed, one must
be careful to avoid an “infinite breakpoint loop” when using tagged-type C
breakpoints while the DBG is armed. If BDM breakpoints are selected,
executing a TRACE1 instruction before the GO instruction is the
recommended way to avoid re-triggering a breakpoint if one does not wish
to de-arm the DBG. If SWI breakpoints are selected, disarming the DBG in
the SWI interrupt service routine is the recommended way to avoid
re-triggering a breakpoint.
TRGSEL
0
0
1
1
0
0
1
1
DBGBRK
MC9S12E256 Data Sheet, Rev. 1.08
Table 16-26. Breakpoint Setup
0
1
0
1
0
1
0
1
Fill trace buffer until trigger address
(no CPU breakpoint — keep running)
Fill trace buffer until trigger address, then a forced breakpoint
request occurs
Fill trace buffer until trigger opcode is about to execute
(no CPU breakpoint — keep running)
Fill trace buffer until trigger opcode about to execute, then a
tagged breakpoint request occurs
Start trace buffer at trigger address
(no CPU breakpoint — keep running)
Start trace buffer at trigger address, a forced breakpoint
request occurs when trace buffer is full
Start trace buffer at trigger opcode
(no CPU breakpoint — keep running)
Start trace buffer at trigger opcode, a forced breakpoint request
occurs when trace buffer is full
NOTE
Type of Debug Run
Chapter 16 Debug Module (DBGV1)
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