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CHAPTER 3 CPU
3.5.7
Procedure for Use of Hardware Interrupt
The settings of the system stack area, resources, interrupt control registers (ICR) are
required for using the hardware interrupt.
I Procedure for Use of Hardware Interrupt
Figure 3.5-7 shows an example of the procedure for use of the hardware interrupt.
1
Setting the system stack area
2
Setting the peripheral function interrupt
ICR setting in interrupt
3
controller
Setting starting operation
4
of perpheral function
Setting enable interrupt
enable bit
5
6
Interrupt request generate
1. Set the system stack area.
2. Set an interrupt of the peripheral with the interrupt request function.
3. Set the interrupt control register (ICR) in the interrupt controller.
4. Set the resource to start operation and the interrupt enable bit to enabled.
5. Set the interrupt level mask register (ILM) and the interrupt enable flag (CCR: I) ready to accept an
interrupt (CCR: I = 1).
6. An interrupt generated from the resource generates a hardware interrupt request.
7. The interrupt controller saves data in the dedicated registers, and processing transits to interrupt
processing.
8. Execute the program for interrupt generation at interrupt processing.
9. Clear the interrupt request from the peripheral.
10.Execute the interrupt return instruction (RETI) to return to the program executed before transition to
interrupt processing.
74
Figure 3.5-7 Procedure for Use of Hardware Interrupt
Start
Processing
by hardware
Setting ILM, I in PS
Main program
Main program
Stack processing
8
branch to interrupt vector
7
9
10
Interrupt processing program
Processing of interrupt for
peripheral function
(execution of interrupt
processing)
Clear of interrupt request
Interrupt return instruction (RETI)
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