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CHAPTER 7 INTERRUPT
7.5
Software Interrupt
When the software interrupt instruction (INT instruction) is executed, the software
interrupt function transfers control from the program being executed by the CPU to the
user-defined interrupt processing program. Hardware interrupt is disabled during
execution of a software interrupt.
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Software Interrupt Activation
●
Software interrupt activation
The INT instruction is used to activate a software interrupt. There is no interrupt request flag or enable flag
for software interrupt requests. When the INT instruction is executed, an interrupt request is always
generated.
●
Hardware interrupt suppression
Since the INT instruction does not have interrupt levels, the interrupt level mask register (ILM) is not
updated. During the execution of the INT instruction, the I flag of the condition code register (CCR) is set
to "0", and hardware interrupts are masked.
To enable hardware interrupts during software interrupt processing, set the I flag to "1" in the software
interrupt processing routine.
●
Software interrupt operation
When the CPU fetches the INT instruction, the software interrupt processing microcode is activated. This
microcode saves the internal CPU registers on the system stack, masks hardware interrupts (CCR: I = 0),
and branches to the corresponding interrupt vector.
See "7.2 Interrupt Causes and Interrupt Vectors", in Chapter 7 for more information about the allocation of
interrupt numbers and interrupt vectors.
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Returning from a Software Interrupt
In the interrupt processing program, when the interrupt return instruction (RETI instruction) is executed,
the 12-byte data saved to the system stack is restored to the dedicated registers and the processing that was
being executed before branching for the interrupt is resumed.
Summary of Contents for MB90460 Series
Page 1: ...The following document contains information on Cypress products ...
Page 3: ......
Page 5: ......
Page 9: ...iv ...
Page 41: ...22 CHAPTER 1 OVERVIEW ...
Page 45: ...26 CHAPTER 2 NOTES ON HANDLING DEVICES ...
Page 83: ...64 CHAPTER 3 CPU ...
Page 95: ...76 CHAPTER 4 RESET ...
Page 107: ...88 CHAPTER 5 CLOCK ...
Page 131: ...112 CHAPTER 6 LOW POWER CONSUMPTION MODE ...
Page 175: ...156 CHAPTER 7 INTERRUPT ...
Page 181: ...162 CHAPTER 8 MODE SETTING ...
Page 223: ...204 CHAPTER 9 I O PORT ...
Page 237: ...218 CHAPTER 10 TIME BASE TIMER ...
Page 247: ...228 CHAPTER 11 WATCHDOG TIMER ...
Page 275: ...256 CHAPTER 12 16 BIT RELOAD TIMER ...
Page 373: ...354 CHAPTER 14 MULTI FUNCTIONAL TIMER ...
Page 485: ...466 CHAPTER 16 PWC Timer ...
Page 531: ...512 CHAPTER 17 UART ...
Page 559: ...540 CHAPTER 19 DELAYED INTERRUPT GENERATOR MODULE ...
Page 589: ...570 CHAPTER 20 8 10 BIT A D CONVERTER ...
Page 601: ...582 CHAPTER 21 ROM CORRECTION FUNCTION ...
Page 633: ...614 CHAPTER 23 512K 1024K BIT FLASH MEMORY ...
Page 645: ...626 CHAPTER 24 EXAMPLE OF F2 MC 16LX MB90F462 F462A F463A CONNECTION FOR SERIAL WRITING ...
Page 715: ...696 APPENDIX ...
Page 716: ...697 INDEX INDEX The index follows on the next page This is listed in alphabetic order ...
Page 739: ......