National Instruments PXI-8170 Series - Manual (Page 39)

© National Instruments Corporation C-1 PXI-8170 Series User Manual
C
PXI-8170 Series
System Resources
This appendix describes the system resources available on the PXI-8170
Series embedded computer and where they are allocated. Because PCI is a
relatively new addition to PCs, this appendix describes how PCI interrupts
fit into a PC architecture before listing the devices that use them.
PCI Interrupts
PCI interrupts are more flexible than ISA interrupts because multiple
devices can share these interrupts. PCI interrupts do not actually connect to
the processor directly; they map through ISA interrupts in the system I/O
module. The interrupt handler for a particular ISA interrupt must know if it
will be acknowledging a PCI device.
Resource Tables
The following tables describe where system resources are assigned.
Table C-1 lists how the ISA interrupts are allocated on the PXI-8170 Series
and whether a PCI interrupt drives them.
Table C-1. PXI-8170 Series ISA Interrupt Resource Allocations
ISA Interrupt PCI Interrupt Device
NMI None Parity
0 None Timer
1 None Keyboard
2 None IRQ Expansion (8–15)
3 PCI Plug and Play PXI Modules
4 None COM1