An Advanced Programmable Interrupt Controller (APIC) is a more intricate Programmable Interrupt Controller (PIC) containing a magnitude more outputs and much more complex priority schemas.
One of the best known APIC architectures, the Intel APIC Architecture, is now replacing the original 8259A PIC in newer x86 PCs.
See also
- Intel 8259
- Programmable Interrupt Controller
- Intel APIC Architecture
- Inter-Processor Interrupt
- Interrupt
- Interrupt Handler
- Interrupt Latency
- Non-Maskable Interrupt
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When working with computer hardware, installing and removinge devices, the system relies on Interrupt Requests (IRQ). There are default settings that are configured in the system BIOS and recognized by the operating system. These default settings can be altered by advanced users. Modern Plug and Play technology has not only reduced the need for concern for these settings, but has virtually eliminated manual configuration.
The system uses 16 default IRQ's.
IRQ 0 - System timer. Reserved for the system. Cannot be changed by a user.
IRQ 1 - Keyboard. Reserved for the system. Cannot be altered even if no keyboard is present or needed.
IRQ 2 - Second IRQ controller. Further explanation pending. IRQ's 8-15 rely on this.
IRQ 3 - COM 2(Default) COM 4(User)
IRQ 4 - COM 1(Default) COM 3(User)
IRQ 5 - Sound card or LPT2(User)
IRQ 6 - Floppy disk controller
IRQ 7 - LPT1(Parallel port)
IRQ 8 - Real time clock
IRQ 9 - Free / Open interrupt / Available
IRQ 10 - Free / Open interrupt / Available
IRQ 11 - Free / Open interrupt / Available
IRQ 12 - PS2 Mouse / If no PS2 mouse is used, this can be used for other periferals
IRQ 13 - Math co-processor. Cannot be changed
IRQ 14 - Primary IDE. If no IDE this can be changed
IRQ 15 - Secondary IDE
More to follow. BILL