86
MC96F6432A
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]. The following process is the flow of whole interrupt service routine.
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
(PCL)
(Interrupt Vector Address L)
(PCH)
(Interrupt Vector Address H)
4
ISR(Interrupt Service Routine) 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
Summary of Contents for MC96F6432A
Page 16: ...16 MC96F6432A ABOV Semiconductor Co Ltd 4 Package Diagram Figure 4 1 48 Pin QFN Package ...
Page 17: ...17 MC96F6432A ABOV Semiconductor Co Ltd Figure 4 2 44 Pin MQFP Package ...
Page 18: ...18 MC96F6432A ABOV Semiconductor Co Ltd Figure 4 3 32 Pin LQFP Package ...
Page 19: ...19 MC96F6432A ABOV Semiconductor Co Ltd Figure 4 4 32 Pin SOP Package ...
Page 20: ...20 MC96F6432A ABOV Semiconductor Co Ltd Figure 4 5 28 Pin SOP Package ...
