8-17
INTERRUPT CONTROL UNIT
Figure 8-8. Interrupt Mask Register
8.4.4
Priority Mask Register
The Priority Mask register (Figure 8-9) contains a three-level field that holds a priority value.
This register allows you to mask interrupts based on their priority levels. Write a priority value
to the PM2:0 field to specify the lowest priority interrupt to be serviced. This disables (masks)
any interrupt source whose priority is lower than the PM2:0 value. After reset, the Priority Mask
register is set to the lowest priority (seven), which enables all interrupts of any priority.
Register Name:
Interrupt Mask Register
Register Mnemonic:
IMASK
Register Function:
Masks individual interrupt sources
Bit
Mnemonic
Bit Name
Reset
State
Function
INT3:0
External
Interrupt
Mask
0000 0
Set a bit to mask (disable) interrupt requests
from the corresponding external interrupt pin.
DMA1:0
DMA
Interrupt
Mask
0
Set to mask (disable) interrupt requests from
the corresponding DMA channel .
TMR
Timer
Interrupt
Mask
0
Set to mask (disable) interrupt requests from
the timers.
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.
A1202-A0
15
0
T
M
R
D
M
A
0
D
M
A
1
I
N
T
0
I
N
T
1
I
N
T
2
I
N
T
3
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...
Страница 81: ......
Страница 127: ......
Страница 128: ...4 Peripheral Control Block...
Страница 129: ......
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...
Страница 229: ......
Страница 253: ......
Страница 254: ...10 Direct Memory Access Unit...
Страница 255: ......
Страница 283: ......
Страница 284: ...11 Math Coprocessing...
Страница 285: ......
Страница 302: ...12 ONCE Mode...
Страница 303: ......
Страница 306: ...A 80C186 Instruction Set Additions and Extensions...
Страница 307: ......
Страница 318: ...B Input Synchronization...
Страница 319: ......
Страница 322: ...C Instruction Set Descriptions...
Страница 323: ......
Страница 371: ......
Страница 372: ...D Instruction Set Opcodes and Clock Cycles...
Страница 373: ......
Страница 396: ...Index...
Страница 397: ......