Main
IRQ Assignment for ATX boards. OLD XT boards had only 8 IRO's
0 System Timer (priority 1)
1 Keyboard controller (priority 2)
2 Programmable interrupt (cascades more irq's)
3 Communications Port COM 2 ***Remember for CompTia****
4 Communications Port COM 1 ***Remember for CompTia****
5 Sound Card or LPT2 ***Remember for CompTia****
6 Floppy Disk controller
7 Printer Port LPT1 ***Remember for CompTia****
8 System CMOS /Real Time clock
9 Available for ISA or PCI devices
10 PCI steering
11 PCI steering
12 PS/2 Mouse Port
13 Numeric Data Processor
14 Primary IDE Channel
15 Secondary IDE Channel