tmp88fw45afg TOSHIBA Semiconductor CORPORATION, tmp88fw45afg Datasheet - Page 47

• Manufacturer Part Number: tmp88fw45afg
• Description: 8 Bit Microcontroller Tlcs-870/x Series
• Manufacturer: TOSHIBA Semiconductor CORPORATION

3.3.3
Figure 3-4 Saving/Restoring General-purpose Registers under Interrupt Processing
Main task
Bank m
Bank m
can be accepted immediately after the interrupt return instruction is executed.
(a) Saving/restoring by register bank changeover
Interrupt return
Interrupt return instructions [RETI]/[RETN] perform as follows.
Interrupt requests are sampled during the final cycle of the instruction being executed. Thus, the next interrupt
Note:When the interrupt processing time is longer than the interrupt request generation time, the interrupt
1. The contents of the program counter and the
program status word are restored from the stack.
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,
and the interrupt nesting flag is changed.
service task is performed but not the main task.
Interrupt return
Interrupt
acceptance
[RETI] Maskable Interrupt Return
Interrupt
service task
Bank m
Bank n
Restore to bank m
automatically by
[RETI]/[RETN]
Switch to bank n by
LD, RBS and n instruction
Switch to bank n
automatically
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1. The contents of the program counter and the
program status word are restored from the stack.
2. The stack pointer is incremented 5 times.
3. The interrupt master enable flag is set to "1" only
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.
4. The interrupt nesting counter is decremented,
and the interrupt nesting flag is changed.
(b) Saving/restoring general-purpose registers using
[RETN] Non-maskable Interrupt Return
Main task
PUSH/POP data transfer instruction
Interrupt return
Interrupt
acceptance
Interrupt
service task
TMP88FW45AFG
Saving
registers
Restoring
registers