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RE: 1 IRQ line for all bridged dev? RE: prob w/PCI add-in cards w /PCI 2PCI bridge on it




>  There are hundreds of PC platforms worldwide which 
>  only support 1 IRQ line (INTA) per PCI slot.  

I've not seen one.  If they exist, they violate the PCI specification.

>From PCI 2.2 and PCI 2.1, Paragraph 2.2.6:  "The system designer must insure
that each INTx# signal from each connector is connected to an input on the
interrupt controller."  Interrupts are optional for add-in boards, not board
slots.

As Brooks stated, all four INTx# signals may be connected to the same line
of an interrupt controller, but they must all be connected.

Bob Shepard
Senior Engineer
Monterey Design Center
Motorola Computer Group 
Bob.Shepard@Motorola.com