Intel 80312 I/O Companion Chip - ECEE

Intel ® 80312 I/O Companion ChipPCI and Peripheral Interrupt Controller Unit2.4.1 PCI Interrupt RoutingThe four secondary PCI interrupt inputs IRQ[3:0] can be routed to either the Intel ® 80200processor interrupt pin, FIQ, or to primary PCI interrupt output pins.Routing of interrupt inputs iscontrolled by the PCI Interrupt Routing Select Register (PIRSR). Table 2-1 summarizes the usageof the bits in the PIRSR.Table 2-1.PCI Interrupt Routing SummaryPIRSR Select Bit Bit Value Descriptionbit 0bit 1bit 2bit 31 S_INTA#/XINT0#/IRQ0 Input Pin routed to FIQ# Output Pin0 S_INTA#/XINT0#/IRQ0 Input Pin routed to P_INTA# Output Pin1 S_INTB#/XINT1#/IRQ1 Input Pin routed to FIQ# Output Pin0 S_INTB#/XINT1#/IRQ1 Input Pin routed to P_INTB# Output Pin1 S_INTC#/XINT2#/IRQ2 Input Pin routed to FIQ# Output Pin0 S_INTC#/XINT2#/IRQ2 Input Pin routed to P_INTC# Output Pin1 S_INTD#/XINT3#/IRQ3 Input Pin routed to FIQ# Output Pin0 S_INTD#/XINT3#/IRQ3 Input Pin routed to P_INTD# Output Pin2.4.2 Intel ® 80312 I/O Companion Chip: External InterruptInterfaceThe external interrupt input interface for the Intel ® 80312 I/O companion chip consists of the pinsshown in Table 2-2:Table 2-2.Interrupt Input Pin DescriptionsSignalS_INTA#/XINT0#/IRQ0S_INTB#/XINT1#/IRQ1S_INTC#/XINT2#/IRQ2S_INTD#/XINT3#/IRQ3DescriptionCanbedirectedtotheP_INTA# output or to FIQ# Output PinCan be directed to the P_INTB# output or to FIQ# Output PinCan be directed to the P_INTC# output or to FIQ# Output PinCan be directed to the P_INTD# output or to FIQ# Output Pin2-4 Developer’s Manual