Interrupt Assignments; Table 1-3. Interrupt Assignments - Dell Dimension XPS H266 Service Manual

1-16 Dell Dimension XPS H233 and XPS H266 Systems Service Manual
I
nterrupt Assignments

Table 1-3. Interrupt Assignments

IRQ Line Used By/Available
IRQ0 Generated by system timer.
IRQ1 Generated by I/O controller to indicate full keyboard output
buffer.
IRQ2 Generated internally by interrupt controller to enable IRQ8
through IRQ15.
IRQ3 Available for use by an expansion card.
IRQ4 Generated by I/O controller to indicate that the device connected
to the serial port requires service (COM1 or COM3).
IRQ5 Default audio IRQ assignment.
IRQ6 Generated by I/O controller to indicate that the diskette drive or
tape drive requires service.
IRQ7 Generated by I/O controller to indicate that the device connected
to the parallel port requires service.
IRQ8 Generated by I/O controller for each tick of the RTC.
IRQ9 Available for use by an expansion card.
IRQ10 Available for use by an expansion card.
IRQ11 Default PCI IRQ assignment.
*
IRQ12 Generated by I/O controller to indicate full mouse output buffer.
IRQ13 Generated by math coprocessor to indicate a coprocessor error.
IRQ14 Generated by a device connected to the primary EIDE interface to
indicate that the device requires service.
IRQ15 Generated by a device connected to the secondary EIDE interface
to indicate that the device requires service. If no device is con-
nected to the secondary EIDE interface, IRQ15 is available for
use by an expansion card.
* The PCI IRQ line is assigned to an available IRQ line after all ISA expansion cards have
been configured. If an ISA expansion card is configured for IRQ11, the PCI IRQ is as-
signed to another available IRQ line.