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Chapter 4 Interrupt (S12ZINTV0)
MC9S12ZVM Family Reference Manual Rev. 1.3
Freescale Semiconductor
139
NOTE
All non I-bit maskable interrupt requests always have higher priority than I-
bit maskable interrupt requests. If an I-bit maskable interrupt request is
interrupted by a non I-bit maskable interrupt request, the currently active
interrupt processing level (IPL) remains unaffected. It is possible to nest
non I-bit maskable interrupt requests, e.g., by nesting SWI, SYS or TRAP
calls.
4.4.2.1
Interrupt Priority Stack
The current interrupt processing level (IPL) is stored in the condition code register (CCW) of the CPU.
This way the current IPL is automatically pushed to the stack by the standard interrupt stacking procedure.
The new IPL is copied to the CCW from the priority level of the highest priority active interrupt request
channel which is configured to be handled by the CPU. The copying takes place when the interrupt vector
is fetched. The previous IPL is automatically restored from the stack by executing the RTI instruction.
4.4.3
Priority Decoder
The INT module contains a priority decoder to determine the relative priority for all interrupt requests
pending for the CPU.
A CPU interrupt vector is not supplied until the CPU requests it. Therefore, it is possible that a higher
priority interrupt request could override the original exception which caused the CPU to request the vector.
In this case, the CPU will receive the highest priority vector and the system will process this exception first
instead of the original request.
If the interrupt source is unknown (for example, in the case where an interrupt request becomes inactive
after the interrupt has been recognized, but prior to the vector request), the vector address supplied to the
CPU defaults to that of the spurious interrupt vector.
NOTE
Care must be taken to ensure that all exception requests remain active until
the system begins execution of the applicable service routine; otherwise, the
exception request may not get processed at all or the result may be a
spurious interrupt request (vector at address (vector base + 0x0001DC)).
4.4.4
Reset Exception Requests
The INT module supports one system reset exception request. The different reset types are mapped to this
vector (for details please refer to the Clock and Power Management Unit module (CPMU)):
1. Pin reset
2. Power-on reset
3. Low-voltage reset
4. Clock monitor reset request
5. COP watchdog reset request
Содержание MC9S12ZVM series
Страница 116: ...Chapter 2 Port Integration Module S12ZVMPIMV1 MC9S12ZVM Family Reference Manual Rev 1 3 116 Freescale Semiconductor ...
Страница 242: ...Chapter 7 ECC Generation Module SRAM_ECCV1 MC9S12ZVM Family Reference Manual Rev 1 3 242 Freescale Semiconductor ...
Страница 384: ...Chapter 10 Supply Voltage Sensor BATSV3 MC9S12ZVM Family Reference Manual Rev 1 3 384 Freescale Semiconductor ...
Страница 484: ...Chapter 13 Programmable Trigger Unit PTUV2 MC9S12ZVM Family Reference Manual Rev 1 3 484 Freescale Semiconductor ...
Страница 662: ...Chapter 17 Gate Drive Unit GDUV4 MC9S12ZVM Family Reference Manual Rev 1 3 662 Freescale Semiconductor ...
Страница 684: ...Chapter 18 LIN Physical Layer S12LINPHYV2 MC9S12ZVM Family Reference Manual Rev 1 3 684 Freescale Semiconductor ...
Страница 740: ...Chapter 19 128 KB Flash Module S12ZFTMRZ128K512V2 MC9S12ZVM Family Reference Manual Rev 1 3 740 Freescale Semiconductor ...
Страница 756: ...Appendix A MCU Electrical Specifications MC9S12ZVM Family Reference Manual Rev 1 3 756 Freescale Semiconductor ...
Страница 772: ...Appendix D LINPHY Electrical Specifications MC9S12ZVM Family Reference Manual Rev 1 3 772 Freescale Semiconductor ...
Страница 776: ...Appendix E GDU Electrical Specifications MC9S12ZVM Family Reference Manual Rev 1 3 776 Freescale Semiconductor ...
Страница 788: ...Appendix I MSCAN Electrical Specifications MC9S12ZVM Family Reference Manual Rev 1 3 788 Freescale Semiconductor ...
Страница 790: ...Appendix J Package Information MC9S12ZVM Family Reference Manual Rev 1 3 790 Freescale Semiconductor ...