Technical data

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Each PCI slot on the riser card has four available or MSMT359 interrupt lines: INTA, INTB, INTC,
and INTD. These are connected to the PCI interrupts, PIRQ0 through PIRQ3, as shown below:
Interrupt Line
Slot 1 Slot 2 Slot 3 Slot 4 Slot 5 Slot 6
INTA PIRQ0 PIRQ1 PIRQ2 PIRQ3 PIRQ0 PIRQ1
INTB PIRQ1 PIRQ2 PIRQ3 PIRQ0 PIRQ1 PIRQ2
INTC PIRQ2 PIRQ3 PIRQ0 PIRQ1 PIRQ2 PIRQ3
INTD PIRQ3 PIRQ0 PIRQ1 PIRQ2 PIRQ3 PIRQ0
ISA Bus
The ISA slots on the riser card MSMT463 accommodate ISA based option boards and a 16-bit wide
expansion bus. The ISA bus or MSMT359 interrupt (IRQ) assignments are defined below.
IRQ
Name IRQ Name
0 System Timer 0 8 Real Time Clock
1 Keyboard Full 9 Spare
2 Cascade input for IRQ8 - IRQ15 10 Vibra 16C Controller
3 COM2, COM4 11 Spare
4 COM1, COM3 12 Mouse
5 Spare 13 Not Available
6 I/O Controller 14 Spare
7 Parallel Port 15 Spare
The spare interrupts listed above may be assigned to PCI and ISA devices. When you add a PCI
device to the system, the interrupt will be automatically assigned by the system BIOS. However, at
least one interrupt must be available for the PCI bus. For increased performance, one interrupt should
be left available for each PCI based controller used in the system. When you add a ISA board, you
must assign the interrupt using the System Configuration Utility and jumpers on the option board.