OVERVIEW OF THE 80C186 FAMILY ARCHITECTURE
2-42
Figure 2-26. Interrupt Sequence
2.3.1.1
Non-Maskable Interrupts
The Non-Maskable Interrupt (NMI) is the highest priority interrupt. It is usually reserved for a
catastrophic event such as impending power failure. An NMI cannot be prevented (or masked)
by software. When the NMI input is asserted, the interrupt processing sequence begins after ex-
ecution of the current instruction completes (see “Interrupt Latency” on page 2-45). The CPU au-
tomatically generates a type 2 interrupt vector.
The NMI input is asynchronous. Setup and hold times are given only to guarantee recognition on
a specific clock edge. To be recognized, NMI must be asserted for at least one CLKOUT period
and meet the correct setup and hold times. NMI is edge-triggered and level-latched. Multiple
NMI requests cause multiple NMI service routines to be executed. NMI can be nested in this man-
ner an infinite number of times.
A1029-0A
Stack
SP
CS
IP
Interrupt Enable Bit
PSW
CS
IP
Trap Flag
Instruction Pointer
Code Segment Register
Processor Status Word
Interrupt
Vector
Table
0 0
2
1
3
4
Содержание 80C186XL
Страница 1: ...80C186XL 80C188XL Microprocessor User s Manual...
Страница 2: ...80C186XL 80C188XL Microprocessor User s Manual 1995...
Страница 18: ...1 Introduction...
Страница 19: ......
Страница 27: ......
Страница 28: ...2 Overview of the 80C186 Family Architecture...
Страница 29: ......
Страница 79: ......
Страница 80: ...3 Bus Interface Unit...
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Страница 127: ......
Страница 128: ...4 Peripheral Control Block...
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Страница 137: ......
Страница 138: ...5 ClockGenerationand Power Management...
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Страница 154: ...6 Chip Select Unit...
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Страница 178: ...7 Refresh Control Unit...
Страница 179: ......
Страница 193: ......
Страница 194: ...8 Interrupt Control Unit...
Страница 195: ......
Страница 227: ......
Страница 228: ...9 Timer Counter Unit...
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Страница 254: ...10 Direct Memory Access Unit...
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Страница 284: ...11 Math Coprocessing...
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Страница 302: ...12 ONCE Mode...
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Страница 306: ...A 80C186 Instruction Set Additions and Extensions...
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Страница 318: ...B Input Synchronization...
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Страница 322: ...C Instruction Set Descriptions...
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Страница 372: ...D Instruction Set Opcodes and Clock Cycles...
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Страница 396: ...Index...
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