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5.5.2 Processing of Internal Peripheral I/O Interrupts by Handlers
(1) Branching to the interrupt handler
When the CPU accepts an interrupt, control branches to the EIT vector entry after hardware
preprocessing as described in Section 4.3, "EIT Processing Procedure." The EIT vector entry for
External Interrupt (EI) is located at address H'0000 0080. This address is where the instruction
(not the jump address) for branching to the beginning of the interrupt processing routine for
External Interrupt (EI) is written.
(2) Processing by interrupt handler
In the External Interrupt (EI) handler, first save the BPC register, PSW register, and general-
purpose registers to the stack.
Next, read out the Interrupt Mask Register (IMASK) and save the read value to the stack. Then
read out the Interrupt Vector Register (IVECT). Always be sure to read out the IMASK before
reading the IVECT. A read of IMASK and that of IVECT both triggers an operation to clear
interrupt requests to the CPU and accept the next interrupt. Furthermore, a read of IVECT
causes NEW_IMASK to be set in the IMASK and the accepted interrupt request to be cleared
(not cleared in the case of level-recognized interrupt sources, however).
The IVECT register has set in it the 16 low-order bits of ICU vector table address for the accepted
interrupt source. Read the IVECT register using a signed halfword load instruction (LDH
instruction) and then the content of the ICU interrupt vector table indicated by the read address.
Make sure the ICU vector table has the start addresses of interrupt handlers for each internal
peripheral I/O written in it beforehand, so that control will branch to the address read from this
table to execute processing by each handler.
When returning from the handler, clear the PSW register IE bit to 0 to disable interrupts and then
restore the IMASK value from the stack.
(3) Identifying the source of interrupt generated
If any internal peripheral I/O has multiple interrupt sources, check the Interrupt Status Register
for each internal peripheral I/O to identify the source of interrupt generated.
(4) Enabling multiple interrupts
To enable another interrupt in an interrupt handler, set the PSW register's IE (Interrupt Enable)
bit to 1 to enable interrupts so that they will be accepted. However, before writing a 1 to the IE bit,
always be sure to save each register (BPC, PSW, general-purpose register, and IMASK) to the
stack.
INTERRUPT CONTROLLER (ICU)
5.5 Description of Interrupt Operation
Содержание M32170F3VFP
Страница 19: ...CHAPTER 1 CHAPTER 1 OVERVIEW 1 1 Outline of the 32170 1 2 Block Diagram 1 3 Pin Function 1 4 Pin Layout ...
Страница 42: ...1 1 24 Ver 0 10 OVERVIEW 1 4 Pin Layout This is a blank page ...
Страница 56: ...2 2 14 Ver 0 10 This is a blank page ...
Страница 88: ...3 3 32 Ver 0 10 ADDRESS SPACE 3 7 Notes on Address Space This is a blank page ...
Страница 192: ...6 6 58 Ver 0 10 INTERNAL MEMORY 6 9 Precautions to Be Taken When Rewriting Flash Memory This is a blank page ...
Страница 270: ...9 9 40 Ver 0 10 DMAC 9 4 Precautions about the DMAC This is a blank page ...
Страница 498: ...10 10 228 Ver 0 10 MULTIJUNCTION TIMERS 10 9 TOM Output related 16 bit Timer This is a blank page ...
Страница 550: ...11 11 52 Ver 0 10 A D CONVERTERS 11 4 Precautions on Using A D Converters This is a blank page ...
Страница 614: ...12 12 64 Ver 0 10 This is a blank page SERIAL I O 12 9 Precautions on Using UART Mode ...
Страница 710: ...14 14 16 Ver 0 10 REAL TIME DEBUGGER RTD 14 4 Typical Connection with the Host This is a blank page ...
Страница 746: ...16 16 20 Ver 0 10 WAIT CONTROLLER 16 3 Typical Operation of the Wait Controller This is a blank page ...
Страница 756: ...17 17 10 Ver 0 10 RAM BACKUP MODE 17 4 Exiting RAM Backup Mode Wakeup This is a blank page ...
Страница 757: ...CHAPTER 18 CHAPTER 18 OSCILLATION CIRCUIT 18 1 Oscillator Circuit 18 2 Clock Generator Circuit ...
Страница 762: ...18 18 6 Ver 0 10 OSCILLATION CIRCUIT 18 2 Clock Generator Circuit This is a blank page ...
Страница 798: ...19 19 36 Ver 0 10 JTAG 19 6 Precautions about Board Design when Connecting JTAG This is a blank page ...
Страница 830: ...21 21 24 Ver 0 10 PRELIMINARY PRELIMINARY This is a blank page ELECTRICAL CHARACTERISTICS 21 5 AC Characteristics ...
Страница 831: ...CHAPTER 22 CHAPTER 22 TYPICAL CHARACTERISTICS 22 1 A D Conversion Characteristics ...
Страница 833: ...Appendix 1 1 Dimensional Outline Drawing APPENDIX 1 APPENDIX 1 MECHANICAL SPECIFICATIONS ...
Страница 837: ...Appendix 2 1 32170 Instruction Processing Time APPENDIX 2 APPENDIX 2 INSTRUCTION PROCESSING TIME ...
Страница 841: ...Appendix 3 1 Precautions about Noise APPENDIX 3 APPENDIX 3 PRECAUTIONS ABOUT NOISE ...