IRQ (Interrupt Request) Definition

DocumentID: 655829
Revision Date: 29-Feb-96 8:29:38 PM

The information in this document applies to:
WordPerfect® 5.1 for DOS

Problem

Solutions: IRQ - Interrupt Request: Interrupt request lines are physical connections between external hardware devices and the interrupt controllers. When a device, such as a floppy controller or a printer needs the attention of the CPU, handshaking signals are sent back and forth until a task is completed. On the PC and XT IBM-compatible systems, there are eight IRQ lines numbered IRQ0 through IRQ7. On the AT and PS/2 systems, there are sixteen IRQ lines numbered IRQ0 through IRQ15. In a particular system, the goal is to configure expansion boards so that each board has its own IRQ line. If you have two serial ports on your system, you know that IRQ3 and IRQ4 are taken. |---------------------------------------------------------------| | IRQ Line | Hardware Device | Interrupt No. | Systems | |----------|------------------------|---------------|-----------| | IRQ0 | System timer | 08h | ALL | | IRQ1 | Keyboard | 09h | ALL | | IRQ2 | INT line from 8259A | 0Ah | AT, PS/2 | | IRQ3 | COM2 Serial Port | 0Bh | ALL | | IRQ4 | COM1 Serial Port | 0Ch | ALL | | IRQ5 | Fixed Disk Controller | 0Dh | PC and XT | | IRQ5 | Reserved | 0Dh | AT, PS/2 | | IRQ6 | Floppy Disk Controller | 0Eh | ALL | | IRQ7 | LPT1 Parallel Port | 0Fh | ALL | | IRQ8 | Real-time Clock | 70h | AT, PS/2 | | IRQ9 | Redirected to IRQ2 | 71h | AT, PS/2 | | IRQ10 | Reserved | 72h | AT, PS/2 | | IRQ11 | Reserved | 73h | AT, PS/2 | | IRQ12 | Mouse | 74h | AT, PS/2 | | IRQ13 | Math Coprocessor | 75h | AT, PS/2 | | IRQ14 | Fixed Disk Controller | 76h | AT, PS/2 | | IRQ15 | Reserved | 77h | AT, PS/2 | |---------------------------------------------------------------| This definition was taken from the public domain program named PC-Glossary.

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