HP Dc7700 HP Compaq dx7300 and dc7700 Business PC Technical Reference Guide, 1 - Page 64

Table 4-7., Maskable Interrupt Priorities and Assignments

Page 64 highlights

System Support 8259 Mode The 8259 mode handles interrupts IRQ0-IRQ15 in the legacy (AT-system) method using 8259-equivalent logic. Table 4-7 lists the standard source configuration for maskable interrupts and their priorities in 8259 mode. If more than one interrupt is pending, the highest priority (lowest number) is processed first. Priority 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 -- Table 4-7. Maskable Interrupt Priorities and Assignments Signal Label Source (Typical) IRQ0 Interval timer 1, counter 0 IRQ1 Keyboard IRQ8- Real-time clock IRQ9 Unused IRQ10 PCI devices/slots IRQ11 Audio codec IRQ12 Mouse IRQ13 Coprocessor (math) IRQ14 Primary IDE controller IRQ15 Sec. IDE I/F controller (not available on SATA units) IRQ3 Serial port (COM2) IRQ4 Serial port (COM1) IRQ5 Network interface controller IRQ6 Diskette drive controller IRQ7 Parallel port (LPT1) IRQ2 NOT AVAILABLE (Cascade from interrupt controller 2) 4-12 www.hp.com Technical Reference Guide

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4-12
www.hp.com
Technical Reference Guide
System Support
8259 Mode
The 8259 mode handles interrupts IRQ0-IRQ15 in the legacy (AT-system) method using
8259-equivalent logic.
Table 4-7 lists the standard source configuration for maskable interrupts
and their priorities in 8259 mode. If more than one interrupt is pending, the highest priority
(lowest number) is processed first.
Table 4-7.
Maskable Interrupt Priorities and Assignments
Priority
Signal Label
Source (Typical)
1
IRQ0
Interval timer 1, counter 0
2
IRQ1
Keyboard
3
IRQ8-
Real-time clock
4
IRQ9
Unused
5
IRQ10
PCI devices/slots
6
IRQ11
Audio codec
7
IRQ12
Mouse
8
IRQ13
Coprocessor (math)
9
IRQ14
Primary IDE controller
10
IRQ15
Sec. IDE I/F controller (not available on SATA units)
11
IRQ3
Serial port (COM2)
12
IRQ4
Serial port (COM1)
13
IRQ5
Network interface controller
14
IRQ6
Diskette drive controller
15
IRQ7
Parallel port (LPT1)
--
IRQ2
NOT AVAILABLE (Cascade from interrupt controller 2)