Fujitsu FR60 Hardware Manual page 54

CHAPTER 2 HANDLING THE DEVICE
■ Precautions on the Debuggers
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Single-step execution of the RETI instruction
In an environment where interrupts frequently occur, only the relevant interrupt processing routines are
executed repeatedly during single-step execution.
As a result, the main routines and programs that have a low interrupt level will not be executed. (For
example, if the RETI is executed in single-step mode with timebase timer interrupts allowed, the break will
always be at the beginning of the timebase routine.)
For stages in which debugging of the relevant interrupt processing routines is not required, disable the
relevant interrupts.
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Break function
If the target address of a hardware break (including event breaks) is the address of the current system stack
pointer or if the target address is set in an area that contains the stack pointer, a break will occur after one
instruction is executed. This applies even when there is no data access instruction in the user program.
To avoid the problem, do not set word access for the area that contains the address of the system stack
pointer as a target of a hardware break (including event breaks).
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Internal ROM (flash memory and MASK ROM)
Note the following points when using an evaluation chip:
• Do not set the internal ROM area as the DMAC transfer destination.
• If the internal ROM area is set as the DMAC transfer destination, the internal ROM area may be
rewritten if a break occurs during DMAC transfer. (The internal ROM area can be set as the DMAC
transfer source.)
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Concurrent occurrence of a software break (INTE instruction) and user interrupt or NMI
If a software break and a user interrupt or NMI occur concurrently, the following problems occur in the
debugger:
• The debugger stops, indicating a point other than the break point set by the user.
• After having stopped, the debugger does not correctly execute processing.
If this problem occurs, use a hardware break in place of a software break. If you use a monitor debugger,
avoid setting a break at the relevant point.
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About the operand break
If there is a stack pointer in an area that is set as operand break of DSU, the system may cause
malfunctions. Do not set the access for the area that contains the address of the system stack pointer as a
target of a data event break.
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