Chapter 3Signals and Pinout Tables
Interrupt Request (IRQ) Lines
Table
IRQ# | Available | Typical Interrupt Source | Connected to Pin |
0 | No | Counter 0 | Not applicable |
1 | No | Keyboard | Not applicable |
2 | No | Cascade Interrupt from Slave PIC | Not applicable |
3 | Yes |
| IRQ3 via SERIRQ or PCI BUS INTx |
4 | Yes |
| IRQ4 via SERIRQ or PCI BUS INTx |
5 | Yes |
| IRQ5 via SERIRQ or PCI BUS INTx |
6 | Yes |
| IRQ6 via SERIRQ or PCI BUS INTx |
7 | Yes |
| IRQ7 via SERIRQ or PCI BUS INTx |
8 | No | Not applicable | |
9 | Note 2 | SCI / Generic | IRQ9 via SERIRQ or PCI BUS INTx |
10 | Yes |
| IRQ10 via SERIRQ or PCI BUS INTx |
11 | Yes |
| IRQ11 via SERIRQ or PCI BUS INTx |
12 | Yes |
| IRQ12 via SERIRQ or PCI BUS INTx |
13 | No | Math processor | Not applicable |
14 | Note 1 | IDE Controller 0 (IDE0) / Generic | IRQ14 or PCI BUS INTx |
15 | Note 1 | IDE Controller 1 (IDE1) / Generic | IRQ15 or PCI BUS INTx |
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In PIC mode, the PCI bus interrupt lines can be routed to any free IRQ.
NOTE If the ATA/IDE configuration is set to enhanced mode in BIOS setup (serial ATA and parallel ATA native mode operation), IRQ14 and 15 are free for PCI/LPC bus.
In ACPI mode, IRQ9 is used for the SCI (System Control Interrupt). The SCI can be shared with a PCI interrupt line.
Table
IRQ# | Available | Typical Interrupt Source | Connected to Pin / Function |
0 | No | Counter 0 | Not applicable |
1 | No | Keyboard | Not applicable |
2 | No | Cascade Interrupt from Slave | Not applicable |
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| PIC |
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3 | Yes |
| IRQ3 via SERIRQ |
4 | Yes |
| IRQ4 via SERIRQ |
5 | Yes |
| IRQ5 via SERIRQ |
6 | Yes |
| IRQ6 via SERIRQ |
7 | Yes |
| IRQ7 via SERIRQ |
8 | No | Not applicable | |
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48 | Reference Manual | COM 830 |