INTERRUPT CONTROL UNIT
8-18
Figure 8-9. Priority Mask Register
8.4.5 In-Service Register
The In-Service register has a bit for each interrupt source. The bits indicate which source’s inter-
rupt handlers are currently executing. The In-Service bit is set when an interrupt is acknowl-
edged; the interrupt handler must clear it with an End-of-Interrupt (EOI) command. The Interrupt
Control Unit uses the In-Service register to support interrupt nesting.
Register Name:
Priority Mask Register
Register Mnemonic:
PRIMSK
Register Function:
Masks lower-priority interrupt sources
Bit
Mnemonic
Bit Name
Reset
State
Function
PM2:0
Priority
Mask
111
Defines a priority-based interrupt mask.
Interrupts whose priority is lower than this value
are masked.
NOTE: Reserved register bits are shown with gray shading. Reserved bits must be written
to a logic zero to ensure compatibility with future Intel products.
A1216-A0
15
0
P
M
0
P
M
1
P
M
2
Содержание 80C186EA
Страница 1: ...80C186EA 80C188EA Microprocessor User s Manual...
Страница 2: ...80C186EA 80C188EA Microprocessor User s Manual 1995...
Страница 19: ......
Страница 20: ...1 Introduction...
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Страница 28: ...2 Overview of the 80C186 Family Architecture...
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Страница 80: ...3 Bus Interface Unit...
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Страница 130: ...4 Peripheral Control Block...
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Страница 140: ...5 ClockGenerationand Power Management...
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Страница 166: ...6 Chip Select Unit...
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Страница 190: ...7 Refresh Control Unit...
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Страница 206: ...8 Interrupt Control Unit...
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Страница 239: ...INTERRUPT CONTROL UNIT 8 32...
Страница 240: ...9 Timer Counter Unit...
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Страница 266: ...10 Direct Memory Access Unit...
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Страница 295: ...DIRECT MEMORY ACCESS UNIT 10 28...
Страница 296: ...11 Math Coprocessing...
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Страница 314: ...12 ONCE Mode...
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Страница 318: ...A 80C186 Instruction Set Additions and Extensions...
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Страница 330: ...B Input Synchronization...
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Страница 334: ...C Instruction Set Descriptions...
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Страница 383: ...INSTRUCTION SET DESCRIPTIONS C 48...
Страница 384: ...D Instruction Set Opcodes and Clock Cycles...
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Страница 408: ...Index...
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