Fujitsu FR60 Hardware Manual page 56

CHAPTER 2 HANDLING THE DEVICE
❍ RETI instruction
Do not neither control register of the instruction cache nor the data access to RAM of the
instruction cache immediately before the instruction of RETI.
❍ Watchdog timer function
The watchdog timer function of this model monitors whether a program holds over a reset within
a specified time. It also resets the CPU if the reset is not held over because of uncontrollable
program operation. After the watchdog timer function is enabled, it keeps operating until a reset
occurs.
The watchdog timer function usually holds over CPU reset automatically when program
execution by the CPU stops. For the relevant exception conditions, see "3.12.7 Peripheral
Circuits of Clock Controller".
The reset by the watchdog timer function might not occur if the above status is caused by
uncontrollable system operation. If it might occur, a reset (INIT) request must be input from the
external INIT pin.
❍ A/D converter
When the device is turned on or returns from a reset or stop, it takes time for the external
capacitor to be charged, requiring the A/D converter to wait for at least 10 ms.
■ Unique to the Evaluation Chip MB91V301A
❍ Tool reset
On an evaluation board, use the chip with INIT and TRST connected together.
❍ Single-stepping the RETI instruction
If an interrupt occurs frequently during single stepping, execute only the relevant processing
routine repeatedly after single-stepping RETI.
interrupt-level programs from being executed.
avoidance purposes.
unnecessary, perform debugging with that interrupt disabled.
❍ Simultaneous occurrences of a software break and a user interrupt/NMI
When a software break and a user interrupt /NMI take place at the same time, the emulator
debugger can cause the following phenomena:
• The debugger stops pointing to a location other than the programmed breakpoints.
• The halted program is not re-executed correctly.
If these phenomena occur, use a hardware break instead of the software break. If the monitor
debugger has been used, avoid setting any break at the relevant location.
❍ Operand break
A stack pointer placed in an area set for a DSU operand break can cause a malfunction. Do not
apply a data event break to access to the area containing the address of a system stack pointer.
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When the debugging of the relevant interrupt routine becomes
This will prevent the main routine and low-
Do not single-step the RETI instruction for