95
CHAPTER 8 INTERRUPTS
8.1.2
Interrupt Processing
When an interrupt request is generated by a peripheral resource, the interrupt controller
passes the interrupt level to the CPU. When the CPU is ready to accept interrupts, it
temporarily halts the program currently being executed and executes an interrupt
service routine.
■
Interrupt Processing
The procedure of processing an interrupt takes the following steps: the generation of an interrupt resource in a
peripheral resource, the execution of the main program, the setting of the interrupt request flag bit, the
evaluation of the interrupt request enable bit, the evaluation of interrupt level (ILR0 to ILR5 and CCR:IL1,
IL0), the checking for any equal-level interrupt request, and the evaluation of the interrupt enable flag (CCR:I).
Figure 8.1-2 illustrates the steps to take for interrupt processing.
Figure 8.1-2 Interrupt Processing Steps
Interrupt
from peripheral
resource?
Peripheral
resource interrupt request
output enabled?
Check interrupt priority and
transfer interrupt level to CPU
Compare interrupt level
with IL bit
START
Run main program
Restore PC and PS
Initialize peripheral resources
Interrupt level higher
than IL value?
I flag = 1?
Clear interrupt request
Execute interrupt processing
RETI
Update IL in PS
PC
←
interrupt vector
Save PC and PS onto stack
Level comparator
Interrupt
controller
AND
Interrupt request
flag
Interrupt request
enabled
Each peripheral resource
Condition code register (CCR)
Comparator
Check
CPU
RAM
Internal data bus
I
IL
Release from stop
mode
Release from sleep
mode
Release from timebase
timer/watch mode
(1)
(2)
(3)
(4)
(5)
(6)
(7)
(3)
(4)
(5)
(6)
(7)
NO
NO
NO
NO
YES
YES
YES
YES
Interrupt service routine
Содержание F2 MC-8FX Family
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Страница 30: ...16 CHAPTER 1 DESCRIPTION 1 FPT 64P M23 FPT 64P M24 2 For the I O circuit type refer to 1 8 I O Circuit Type ...
Страница 34: ...20 CHAPTER 1 DESCRIPTION ...
Страница 35: ...21 CHAPTER 2 HANDLING DEVICES This chapter gives notes on using 2 1 Device Handling Precautions ...
Страница 38: ...24 CHAPTER 2 HANDLING DEVICES ...
Страница 39: ...25 CHAPTER 3 MEMORY SPACE This chapter describes memory space 3 1 Memory Space 3 2 Memory Map ...
Страница 43: ...29 CHAPTER 4 MEMORY ACCESS MODE This chapter describes the memory access mode 4 1 Memory Access Mode ...
Страница 56: ...42 CHAPTER 5 CPU ...
Страница 73: ...59 CHAPTER 6 CLOCK CONTROLLER ...
Страница 96: ...82 CHAPTER 6 CLOCK CONTROLLER ...
Страница 104: ...90 CHAPTER 7 RESET ...
Страница 105: ...91 CHAPTER 8 INTERRUPTS This chapter explains the interrupts 8 1 Interrupts ...
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Страница 218: ...204 CHAPTER 13 WATCH PRESCALER ...
Страница 257: ...243 CHAPTER 16 8 16 BIT COMPOSITE TIMER ...
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Страница 382: ...368 CHAPTER 21 UART SIO DEDICATED BAUD RATE GENERATOR ...
Страница 390: ...376 CHAPTER 22 I2C ...
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Страница 430: ...416 CHAPTER 23 10 BIT A D CONVERTER ...
Страница 476: ...462 CHAPTER 24 LCD CONTROLLER ...
Страница 482: ...468 CHAPTER 25 LOW VOLTAGE DETECTION RESET CIRCUIT ...
Страница 494: ...480 CHAPTER 26 CLOCK SUPERVISOR ...
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Страница 532: ...518 CHAPTER 27 REAL TIME CLOCK ...
Страница 536: ...522 CHAPTER 28 256 KBIT FLASH MEMORY ...
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Страница 564: ...550 CHAPTER 29 EXAMPLE OF SERIAL PROGRAMMING CONNECTION ...
Страница 595: ...581 INDEX INDEX The index follows on the next page This is listed in alphabetic order ...
Страница 596: ...582 INDEX Index ...
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Страница 599: ...585 Pin Function Index V2 LCD power supply driving pin 2 439 V3 LCD power supply driving pin 3 439 ...
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