INTERRUPTS
11-18
The IMSK register must be saved and cleared when expanded mode inputs request a priority-31
interrupt. Priority-31 interrupts are interrupted by other priority-31 interrupts. In expanded mode,
the interrupt pins are level-activated. For level-activated interrupt inputs, instructions within the
interrupt handler are typically responsible for causing the source to deactivate. When these
priority-31 interrupts are not masked, another priority-31 interrupt is signaled and serviced before
the handler can deactivate the source. The first instruction of the interrupt handling procedure is
never reached, unless the option is selected to clear the IMSK register on entry to the interrupt.
Another use of the mask is to lock out other interrupts when executing time-critical portions of an
interrupt handling procedure. All hardware-generated interrupts are masked until software
explicitly replaces the mask.
The processor does not restore r3 to the IMSK register when the interrupt return is executed. When
the IMSK register is cleared, the interrupt handler must restore the IMSK register to enable
interrupts after return from the handler.
11.7
EXTERNAL INTERFACE DESCRIPTION
This section describes the physical characteristics of the interrupt inputs. The i960 Jx processor
provides eight external interrupt pins and one non-maskable interrupt pin for detecting external
interrupt requests. The eight external pins can be configured as dedicated inputs, where each pin is
capable of requesting a single interrupt. The external pins can also be configured in an expanded
mode, where the value asserted on the external pins represents an interrupt vector number. In this
mode, up to 240 values can be directly requested with the interrupt pins. The external interrupt
pins can be configured in mixed mode. In this mode, some pins are dedicated inputs and the
remaining pins are used in expanded mode.
11.7.1
Pin Descriptions
The interrupt controller provides nine interrupt pins:
XINT[7:0]
External Interrupt (input) - These eight pins cause interrupts to be requested.
Pins are software configurable for three modes: dedicated, expanded, mixed.
Each pin can be programmed as an edge- or level-detect input. Also, a debounce
sampling mode for these pins can be selected under program control.
NMI
Non-Maskable Interrupt (input) - This edge-activated pin causes a non-maskable
interrupt event to occur. NMI is the highest priority interrupt recognized. A
debounce sampling mode for NMI can be selected under program control. This
pin is internally synchronized.
External interrupt pin functions XINT[7:0] depend on the operation mode (expanded, dedicated or
mixed) and on several other options selected by setting ICON register bits.
Содержание i960 Jx
Страница 1: ...Release Date December 1997 Order Number 272483 002 i960 Jx Microprocessor Developer s Manual ...
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Страница 25: ...1 INTRODUCTION ...
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Страница 35: ...2 DATA TYPES AND MEMORY ADDRESSING MODES ...
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Страница 47: ...3 PROGRAMMING ENVIRONMENT ...
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Страница 73: ...4 CACHE AND ON CHIP DATA RAM ...
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Страница 85: ...5 INSTRUCTION SET OVERVIEW ...
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Страница 111: ...6 INSTRUCTION SET REFERENCE ...
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Страница 195: ...INSTRUCTION SET REFERENCE 6 83 6 Opcode mov 5CCH REG movl 5DCH REG movt 5ECH REG movq 5FCH REG See Also LOAD STORE lda ...
Страница 233: ...7 PROCEDURE CALLS ...
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Страница 257: ...8 FAULTS ...
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Страница 291: ...9 TRACING AND DEBUGGING ...
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Страница 309: ...10 TIMERS ...
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Страница 325: ...11 INTERRUPTS ...
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Страница 369: ...12 INITIALIZATION AND SYSTEM REQUIREMENTS ...
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Страница 413: ...13 MEMORY CONFIGURATION ...
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Страница 429: ...14 EXTERNAL BUS ...
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Страница 469: ...15 TEST FEATURES ...
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Страница 493: ...A CONSIDERATIONS FOR WRITING PORTABLE CODE ...
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Страница 503: ...B OPCODES AND EXECUTION TIMES ...
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Страница 515: ...C MACHINE LEVEL INSTRUCTION FORMATS ...
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Страница 523: ...D REGISTER AND DATA STRUCTURES ...
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Страница 551: ...GLOSSARY ...
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Страница 561: ...INDEX ...
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