Abov MC97F60128 User Manual

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MC97F60128
ABOV Semiconductor Co., Ltd.
10.5 Interrupt Sequence
An interrupt request is held until the interrupt is accepted or the interrupt latch is cleared to ‘0’ by a reset or an
instruction. Interrupt acceptance always generates at last cycle of the instruction. So instead of fetching the current
instruction, CPU executes internally LCALL instruction and saves the PC at stack. For the interrupt service routine, the
interrupt controller gives the address of LJMP instruction to CPU. Since the end of the execution of current instruction,
it needs 3~9 machine cycles to go to the interrupt service routine. The interrupt service task is terminated by the
interrupt return instruction [RETI]. Once an interrupt request is generated, the following process is performed.
Figure 10.3 Interrupt Sequence Flow
Saves PC value in order to continue
process again after executing ISR
IE.EA Flag 0
1
Program Counter low Byte
SP  SP + 1, M(SP)  (PCL)
2
Program Counter high Byte
SP  SP + 1, M(SP)  (PCH)
3
Interrupt Vector Address occurrence
(Interrupt Vector Address)
4
ISR(Interrupt Service Routine) move, execute
5
Return from ISR
RETI
6
Program Counter high Byte recovery
(PCH)  M(SP), SP  SP - 1
7
Main Program execution
10
Program Counter low Byte recovery
(PCL)  M(SP), SP  SP – 1
8
IE.EA Flag 1
9

Abov MC97F60128 Specifications

General

Brand	Abov
Model	MC97F60128
Category	Microcontrollers
Language	English