Interrupt Controller (INTC)
MPC5606S Microcontroller Reference Manual, Rev. 7
Freescale Semiconductor
783
21.7.7.2
Scheduling an ISR on another processor
Because the SET
x
bits in the INTC_SSCIR
x
_
x
are memory-mapped, processors in multiple-processor
systems can schedule ISRs on the other processors. One application is that one processor wants to
command another processor to perform a piece of work and the initiating processor does not need to use
the results of that work. If the initiating processor is concerned that the processor executing the software
configurable ISR has not completed the work before asking it to again execute the ISR, it can check if the
corresponding CLR
x
bit in INTC_SSCIR
x
_
x
is asserted before again writing a 1 to the SET
x
bit.
Another application is the sharing of a block of data. For example, a first processor has completed
accessing a block of data and wants a second processor to then access it. Furthermore, after the second
processor has completed accessing the block of data, the first processor again wants to access it. The
accesses to the block of data must be done coherently. To do this, the first processor writes a 1 to a SET
x
bit on the second processor. After accessing the block of data, the second processor clears the
corresponding CLR
x
bit and then writes 1 to a SET
x
bit on the first processor, informing it that it can now
access the block of data.
21.7.8
Lowering priority within an ISR
A common method for avoiding preemptive scheduling inefficiencies with an ISR whose work spans
multiple priorities (see
Section 21.7.7.1, Scheduling a lower priority portion of an ISR)
is to lower the
current priority. However, the INTC has a LIFO whose depth is determined by the number of priorities.
NOTE
Lowering the PRI value in INTC_CPR within an ISR to below the ISR’s
corresponding PRI value in INTC_PSR0_3–INTC_PSR292_293 allows
more preemptions than the LIFO depth can support.
Therefore, the INTC does not support lowering the current priority within an ISR as a way to avoid
preemptive scheduling inefficiencies.
21.7.9
Negating an Interrupt Request Outside of its ISR
21.7.9.1
Negating an Interrupt Request as a Side Effect of an ISR
Some peripherals have flag bits that can be cleared as a side effect of servicing a peripheral interrupt
request. For example, reading a specific register can clear the flag bits and their corresponding interrupt
requests. This clearing as a side effect of servicing a peripheral interrupt request can cause the negation of
other peripheral interrupt requests besides the peripheral interrupt request whose ISR presently is
executing. This negating of a peripheral interrupt request outside of its ISR can be a desired effect.
21.7.9.2
Negating multiple interrupt requests in one ISR
An ISR can clear other flag bits besides its own. One reason that an ISR clears multiple flag bits is because
it serviced those flag bits, and therefore the ISRs for these flag bits do not need to be executed.
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Страница 82: ...Memory Map MPC5606S Microcontroller Reference Manual Rev 7 80 Freescale Semiconductor...
Страница 112: ...Signal Description MPC5606S Microcontroller Reference Manual Rev 7 110 Freescale Semiconductor...
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Страница 182: ...Boot Assist Module BAM MPC5606S Microcontroller Reference Manual Rev 7 180 Freescale Semiconductor...
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Страница 524: ...Enhanced Direct Memory Access eDMA MPC5606S Microcontroller Reference Manual Rev 7 522 Freescale Semiconductor...
Страница 546: ...Error Correction Status Module ECSM MPC5606S Microcontroller Reference Manual Rev 7 544 Freescale Semiconductor...
Страница 669: ...Flash Memory MPC5606S Microcontroller Reference Manual Rev 7 Freescale Semiconductor 667...
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Страница 882: ...LIN Controller LINFlex MPC5606S Microcontroller Reference Manual Rev 7 880 Freescale Semiconductor...
Страница 901: ...Memory Protection Unit MPU MPC5606S Microcontroller Reference Manual Rev 7 Freescale Semiconductor 899...
Страница 902: ...Memory Protection Unit MPU MPC5606S Microcontroller Reference Manual Rev 7 900 Freescale Semiconductor...
Страница 955: ...Mode Entry Module MC_ME MPC5606S Microcontroller Reference Manual Rev 7 Freescale Semiconductor 953...
Страница 956: ...Mode Entry Module MC_ME MPC5606S Microcontroller Reference Manual Rev 7 954 Freescale Semiconductor...
Страница 1072: ...Quad Serial Peripheral Interface QuadSPI MPC5606S Microcontroller Reference Manual Rev 7 1070 Freescale Semiconductor...
Страница 1096: ...Reset Generation Module MC_RGM MPC5606S Microcontroller Reference Manual Rev 7 1094 Freescale Semiconductor...
Страница 1106: ...Real Time Clock RTC API MPC5606S Microcontroller Reference Manual Rev 7 1104 Freescale Semiconductor...
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Страница 1213: ...System Integration Unit Lite SIUL MPC5606S Microcontroller Reference Manual Rev 7 Freescale Semiconductor 1211...
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