Appendix D System Assignments
79
D.2
DMA Channel Assignments
Table D-2: DMA channel assignments
Channel
Function
0
Available
1
Available
2
Floppy disk (8-bit transfer)
3
Available
4
Cascade for DMA controller 1
5
Available
6
Available
7
Available
* Audio DMA select 0, 1 or 3
D.3
Interrupt Assignments
Table D-3: Interrupt assignments
Interrupt#
Interrupt source
IRQ 0
Interval timer
IRQ 1
Keyboard
IRQ 2
Interrupt from controller 2 (cascade)
IRQ 8
Real-time clock
IRQ 9
Cascaded to INT 0A (IRQ 2)
IRQ 10
Available
IRQ 11
Watchdog Timer
IRQ 12
PS/2 mouse (non-releasable)
IRQ 13
INT from co-processor
IRQ 14
Fixed disk controller (primary)
IRQ 15
Fixed disk controller (secondary)
IRQ 3
Serial communication port 2
IRQ 4
Serial communication port 1
IRQ 5
Parallel port 2
IRQ 6
Diskette controller (FDC)
IRQ 7
Parallel port 1 (print port)
* PNP audio IRQ select: 5, 7, 9 or 10
* Ethernet function is auto-sensing
