Fujitsu MB91401 Datasheet page 28

MB91401
NOTES OF DEBUG
Step execution of RETI instruction
In an environment where interrupts frequently occur during single-step execution, only the relevant interrupt
processing routines are executed repeatedly during single-step execution of the RETI instruction. This will prevent
the main routine and low-interrupt-level programs from being executed.
Do not execute step of RETI instruction for escape.
When the relevant interrupt routine no longer requires being debugged, disable the relevant interrupt and perform
debugging.
Operand break
Do not set the access which is used for area, including the address of system stack pointer, to the target of data
event break.
Interrupt handler to NMI request (tool)
To prevent the malfunction because of the noise problem of DSU pin when ICE is unconnected, the following
programs are added to the interrupt handler by the cause flag, which is only set by the break request from ICE.
ICE can be used even if this program is added.
Location to added
The following interrupt handler
Interrupt resource
Interrupt number
Offset
TBR is default address. : 000FFFC8
Additional program
STM (R0, R1)
LDI #B00 , R0 ; B00
H
LDI #0, R1
STB R1, @R0 ; Clear the break resource register.
LDM (R0, R1)
RETI
Trace mode
If the trace mode is set to "Full trace mode" during debug (in full trace mode, built-in FIFO is used as output
buffer, the trace memory of the main body of ICE is used, and the trace data lost is not occurred), the electric
current is increased and D-busDMA access may be lost.
Also, the trace data lost may be occurred.
To take the measures, do not set full trace mode.
Simultaneous generation of a software break and a user interrupt/NMI
When a software break and a user interrupt/NMI occur simultaneously, the emulator debugger may react as
follows.
• The debugger stops pointing to a location other than the programmed breakpoints.
• The halted program is not re-executed correctly.
When these problems are occurred, not only the software break, the hardware break should also be used. Do
not set the break to the corresponding location when using monitor debugger.
28
: NMI request (tool)
: 13 (decimal), 0D (hexadecimal)
: 3C8
H
H
is address of the break resource register.
H
Prelminary
2004.11.12