98
CHAPTER 8 INTERRUPTS
8.1.4
Interrupt Processing Time
The time between an interrupt request being generated and control being passed to the
interrupt processing routine is equal to the sum of the time until the currently executing
instruction completes and the interrupt handling time (time required to initiate interrupt
processing). This time consists of a maximum of 26 machine clock cycles.
■
Interrupt Processing Time
The interrupt request sampling wait time and interrupt handling time intervene between the occurrence and
acceptance of an interrupt request and the execution of the relevant interrupt service routine.
●
Interrupt request sampling wait time
Whether an interrupt request has occurred is determined through the sampling of the interrupt request
during the last cycle of each instruction. The CPU cannot therefore recognize interrupt requests during the
execution of each instruction. The maximum length of this delay occurs if the interrupt request is generated
immediately after the DIVU instruction requiring the longest instruction cycle (17 machine clock cycles)
starts executing.
●
Interrupt handling time
After receiving an interrupt, the CPU requires 9 machine clock cycles to perform the following interrupt
processing setup:
•
Saves the program counter (PC) and program status (PS) values.
•
Sets the PC to the start address (interrupt vector) of interrupt service routine.
•
Updates the interrupt level bits (PS:CCR:IL1, IL0) in the program status (PS) register.
Figure 8.1-4 Interrupt Processing Time
When an interrupt request is generated immediately after the beginning of execution of the DIVU instruction
requiring the longest execution cycle (17 machine clock cycles), it takes an interrupt processing time of
17+9=26 machine clock cycles.However, if you do not use the DIVU or MULU instructions in your pro-
gram, the
maximum interrupt processing time becomes
7 + 9=16
machine clock cycles.
The machine clock changes depending on the clock mode and main clock speed switching (gear function).
For details, refer to CHAPTER 6 CLOCK CONTROLLER.
CPU operation
Interrupt wait time
Interrupt request
sampling wait time
Normal instruction execution
Interrupt handling time
(9 machine clock cycles)
Interrupt handling
Interrupt service routine
Interrupt request generated
: Last instruction cycle in which the instruction request is sampled
Summary of Contents for F2 MC-8FX Family
Page 2: ......
Page 4: ......
Page 34: ...20 CHAPTER 1 DESCRIPTION ...
Page 38: ...24 CHAPTER 2 HANDLING DEVICES ...
Page 39: ...25 CHAPTER 3 MEMORY SPACE This chapter describes memory space 3 1 Memory Space 3 2 Memory Map ...
Page 56: ...42 CHAPTER 5 CPU ...
Page 73: ...59 CHAPTER 6 CLOCK CONTROLLER ...
Page 96: ...82 CHAPTER 6 CLOCK CONTROLLER ...
Page 104: ...90 CHAPTER 7 RESET ...
Page 105: ...91 CHAPTER 8 INTERRUPTS This chapter explains the interrupts 8 1 Interrupts ...
Page 174: ...160 CHAPTER 10 TIMEBASE TIMER ...
Page 184: ...170 CHAPTER 10 TIMEBASE TIMER ...
Page 218: ...204 CHAPTER 13 WATCH PRESCALER ...
Page 257: ...243 CHAPTER 16 8 16 BIT COMPOSITE TIMER ...
Page 261: ...247 CHAPTER 16 8 16 BIT COMPOSITE TIMER ...
Page 288: ...274 CHAPTER 16 8 16 BIT COMPOSITE TIMER ...
Page 301: ...287 CHAPTER 17 16 BIT PPG TIMER ...
Page 316: ...302 CHAPTER 17 16 BIT PPG TIMER ...
Page 382: ...368 CHAPTER 21 UART SIO DEDICATED BAUD RATE GENERATOR ...
Page 390: ...376 CHAPTER 22 I2C ...
Page 395: ...381 CHAPTER 22 I2C ...
Page 399: ...385 CHAPTER 22 I2C ...
Page 430: ...416 CHAPTER 23 10 BIT A D CONVERTER ...
Page 476: ...462 CHAPTER 24 LCD CONTROLLER ...
Page 482: ...468 CHAPTER 25 LOW VOLTAGE DETECTION RESET CIRCUIT ...
Page 494: ...480 CHAPTER 26 CLOCK SUPERVISOR ...
Page 507: ...493 CHAPTER 27 REAL TIME CLOCK ...
Page 523: ...509 CHAPTER 27 REAL TIME CLOCK ...
Page 532: ...518 CHAPTER 27 REAL TIME CLOCK ...
Page 536: ...522 CHAPTER 28 256 KBIT FLASH MEMORY ...
Page 554: ...540 CHAPTER 28 256 KBIT FLASH MEMORY ...
Page 564: ...550 CHAPTER 29 EXAMPLE OF SERIAL PROGRAMMING CONNECTION ...
Page 595: ...581 INDEX INDEX The index follows on the next page This is listed in alphabetic order ...
Page 596: ...582 INDEX Index ...
Page 597: ...583 INDEX ...
Page 600: ...586 Pin Function Index ...
Page 602: ......