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3 interrupt controller – SMC Networks 486DX4 User Manual

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AR-B1462 User¡

¦s Guide

2-2

2.3 INTERRUPT CONTROLLER

The equivalent of two 8259 Programmable Interrupt Controllers (PIC) are included on the AR-B1462 board. They
accept requests from peripherals, resolve priorities on pending interrupts in service, issue interrupt requests to the
CPU, and provide vectors which are used as acceptance indices by the CPU to determine which interrupt service
routine to execute.

Following is the system information of interrupt levels:

IRQ8 : Real time clock
IRQ9 : Rerouting to INT 0Ah from hardware IRQ2
IRQ10 : Reserved for LAN
IRQ11 : Serial port 4
IRQ12 : spare (PS/2 mouse)
IRQ13 : Math. coprocessor
IRQ14 : Hard disk adapter
IRQ15 : spare (Watchdog Timer)

In

Interrupt Level

NMI

CTRL1

IRQ 0
IRQ 1
IRQ 2

IRQ 3
IRQ 4
IRQ 5
IRQ 6
IRQ 7

CTRL2

Parity check

Description

Serial port 2
Serial port 1
Serial port 3
Floppy disk adapter
Parallel port 1

System timer interrupt from timer 8254
Keyboard output buffer full

Figure 2-1 Interrupt Controller

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