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 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...
Страница 139: ......
Страница 154: ...6 Chip Select Unit...
Страница 155: ......
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 253: ......
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...
Страница 319: ......
Страница 322: ...C Instruction Set Descriptions...
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Страница 371: ......
Страница 372: ...D Instruction Set Opcodes and Clock Cycles...
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Страница 396: ...Index...
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