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Interrupts and ISA Bus Addresses
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6 Interrupts and ISA Bus Addresses
This section lists the system and I/O interrupt assignments. It also lists the physical
AlphaPC 164 I/O space assignments.
6.1 Interrupts
Table 24 lists each AlphaPC 164 ISA interrupt and its source.
1
The # symbol indicates an active low signal.
Table 24 ISA Interrupts
Interrupt Number
Interrupt Source
IRQ0
Internal timer 1
IRQ1
Keyboard
IRQ2
Interrupt from controller 2
IRQ3
COM2
IRQ4
COM1
IRQ5
Available
IRQ6
Diskette
IRQ7
Parallel port
IRQ8#
1
Reserved
IRQ9
Available
IRQ10
Available
IRQ11
Available
IRQ12
Mouse
IRQ13
Available
IRQ14
IDE
IRQ15
IDE