Technical Information 1-21
Table 1-7 Interrupt Level Assignments*
Interrupt Priority
System Resource
10
Windows Sound System*
11
User available
12
Onboard mouse port (if present, else user available)
13
Reserved, math coprocessor
14
Primary IDE (if present, else user available)
15
Secondary IDE (if present, else user available)
* In Plug and Play systems, these interrupts are typical but may vary by configuration.
DMA settings are given in Table 1-8.
Table 1-8 DMA Settings*
DMA Setting
Device
0
Audio
1
Audio/Parallel Port
2
Diskette Drive
3
Parallel Port (for ECP or EPP)/Audio
4
Reserved
Cascade Channel
5
Available
6
Available
7
Available
* In Plug and Play systems, these settings are typical but may vary by configuration.
PCI Interrupt Routing Map
This subsection describes interrupt sharing and how the interrupt signals are connected
between the PCI expansion slots and onboard PCI devices. The PCI specification describes
how interrupts can be shared between devices attached to the PCI bus. In most cases, the
small amount of latency added by interrupt sharing does not affect the operation or
throughput of the devices. In some special cases, where maximum performance is needed
from a device, a PCI device should not share an interrupt with other PCI devices. Use the
following information to avoid sharing an interrupt with a PCI add-in card.