tmp88ch40img TOSHIBA Semiconductor CORPORATION, tmp88ch40img Datasheet - Page 35

• Manufacturer Part Number: tmp88ch40img
• Description: 8 Bit Microcontroller
• Manufacturer: TOSHIBA Semiconductor CORPORATION

3.3.3 Interrupt return
Figure 3-4 Saving/Restoring General-purpose Registers under Interrupt Processing
Main task
Bank m
Bank m
(a) Saving/restoring by register bank changeover
rupt can be accepted immediately after the interrupt return instruction is executed.
Interrupt return instructions [RETI]/[RETN] perform as follows.
Interrupt requests are sampled during the final cycle of the instruction being executed. Thus, the next inter-
Note: When the interrupt processing time is longer than the interrupt request generation time, the interrupt service
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,
task is performed but not the main task.
Interrupt return
Interrupt
acceptance
program status word are restored from the stack.
and the interrupt nesting flag is changed.
[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
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,
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.
(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
TMP88CH40IMG
Saving
registers
Restoring
registers