Справочник Пользователя для National Instruments PXI-8170 Series

Скачать
Страница из 67
© National Instruments Corporation
C-1
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