National Instruments 800 Series - Manual (Page 45)

© National Instruments Corporation B-1 VXIpc 800 Series User Manual
Appendix
B
VXIpc 800 Series
System Resources
This appendix describes what system resources are available on the
VXIpc 800 Series 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 can be shared by multiple devices and are therefore more
flexible than ISA interrupts. They do not actually connect to the
processor directly; they are instead mapped 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
This section provides tables describing where system resources are
assigned. Table B-1 lists how the ISA interrupts are allocated on the
VXIpc 800 Series and whether they are driven by a PCI interrupt.
Table B-2 lists DMA channel allocation, and Table B-3 gives the I/O
address map.
Table B-1. VXIpc 800 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 None COM2
4 None COM1