tmp88cu74 TOSHIBA Semiconductor CORPORATION, tmp88cu74 Datasheet - Page 34

• Manufacturer Part Number: tmp88cu74
• Description: Cmos 8-bit Microcontroller
• Manufacturer: TOSHIBA Semiconductor CORPORATION

1.5.2
1. The contents of the program counter and the
2. The stack pointer is incremented 5 times.
3. The interrupt master enable flag is set to “1”.
4. The interrupt nesting counter is decremented,
(3) Interrupt return
Software Interrupt (INTSW)
interrupt processing (INTSW is highest prioritized interrupt). However, if processing of a
non-maskable interrupt is already underway, executing the SWI instruction will not
generate a software interrupt but will result in the same operation as the [NOP]
instruction.
Note: To use the SWI instruction for software break in the development tool, software interrupt
1.
2.
program status word are restored from the
stack.
and the interrupt nesting flag is changed.
Executing the [SWI] instruction generates a software interrupt and immediately starts
Use the [SWI] instruction only for detection of the address error or for debugging.
[RETI] Maskable interrupt return
executed. Thus, the next interrupt can be accepted immediately after the interrupt
return instruction is executed.
Address error detection
from a non-existent memory address. Code FFH is the SWI instruction, so a software
interrupt is generated and an address error is detected. The address error detection
range can be further expanded by writing FFH to unused areas of the program memory.
Address-trap reset is generated in case that an instruction is fetched from RAM or SFR
areas.
Debugging
break point setting address.
Note: When the interrupt processing time is longer than the interrupt request generation
The interrupt return instructions [RETI]/[RETN] perform the following operations.
Interrupt requests are sampled during the final cycle of the instruction being
FFH is read if for some cause such as noise the CPU attempts to fetch an instruction
Debugging efficiency can be increased by placing the SWI instruction at the software
always generates even if the non-maskable interrupt is in progress.
time, the interrupt service task is performed but not the main task.
88CU74-34
1. The contents of the program counter and
2. The stack pointer is incremented 5 times.
3. The interrupt master enable flag is set to “1” only
4. The interrupt nesting counter is decremented,
[RETN] Non-maskable interrupt return
program status word are restored from the
stack.
when a non-maskable interrupt is accepted in
interrupt enable status. However, the interrupt
master enable flag remains at “0” when so clear
by an interrupt service program.
and the interrupt nesting flag is changed.
TMP88CU74
2007-10-19
2003-02-17