Digital DECpc LPv/LPv+
Device Mapping
MCS Logistics Engineering - Nijmegen
63
Computer Interrupt Levels
Priority
Interrupt Controller
Interrupt Number
Interrupt Source
1
1
IRQ0
Timer tick
2
1
IRQ1
Keyboard controller
1
IRQ2
Cascade interrupt
3
2
IRQ8
Real-time clock (RTC)
4
2
IRQ9
Reserved
5
2
IRQ10
Reserved
6
2
IRQ11
Reserved
7
2
IRQ12
Mouse interrupt
8
2
IRQ13
Math coprocessor
9
2
IRQ14
Hard disk drive
10
2
IRQ15
Reserved
11
1
IRQ3
COM2, COM4
12
1
IRQ4
COM1, COM3
13
1
IRQ5
Reserved
14
1
IRQ6
Diskette drive
15
1
IRQ7
LPT1, LPT2, LPT3
DMA Channel Assignment
Channel
Controller
Function
0
1
Refresh
1
1
Not used
2
1
Diskette controller
3
1
ECP (optional)
4
2
Cascade DMA
5
2
Not used
6
2
Not used
7
2
Not used
