Freescale Semiconductor Microcontrollers - Manual (Page 379)

HC08 P&E Multilink/Cyclone Pro Connection
Connection Procedure
379 Microcontrollers Debugger Manual
Debugging Limitations
The following limitations are inherent in MON08 debugging. Observe these restrictions
carefully.
1. Do not step a command that branches to itself.
2. Do not step a software interrupt (SWI) command.
3. The hardware breakpoint registers are reserved for use by the debugger. Attempting to
use these registers for other purposes may not work.
4. Be careful about showing peripheral status and data registers in the memory or
variables window. A refresh of the window reads these registers and may cause the
clearing of flags.
5. The debug monitor built into CPU08 processors uses up to 13 bytes of the stack. Do
not write to these addresses from (SP-13) to SP. To load a program into RAM, move
the stack to the end of RAM.
6. If interrupts are turned on during stepping, the debugger does not step into the
interrupt. Instead, it executes the whole interrupt and stops on the command following
the interrupt.
7. Do not set hardware breakpoints within the monitor ROM area itself. Hardware
breakpoints set in this area do not function properly.
Debugging Tips
The following tips may prove useful:
1. Single stepping is allowed in both RAM or ROM.
2. The first breakpoint set is always a hardware breakpoint, and any additional
breakpoints set are software breakpoints. To make sure that a hardware breakpoint is
being set, make sure only one breakpoint is being used.
3. Hardware breakpoints can stop execution in ROM or RAM. Software breakpoints can
stop execution only in RAM.
4. Experiment with the register interpreter. Use the View Register Files option in the
MultilinkCyclonePro menu.
5. Executing an SWI instruction while running is functionally equivalent to hitting a
breakpoint, except that execution stops at the instruction following the SWI.
6. A hardware breakpoint may be used to trap a data read/write to anywhere in the
memory map. The debugger stops at the instruction after the one that accesses the data
location.
7. When the target board is reset by the debugger, power to the microcontroller may be
turned off for a short duration. Although much of RAM may look the same, some
values may have changed.