Sony 486DX User Manual

AR-B1474 User¡

¦s Guide

2-2

The equivalent of two 8259 Programmable Interrupt Controllers (PIC) are included on the AR-B1474 card.  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 : Spare
IRQ11 : Spare
IRQ12 : Spare
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
Parallel port 2
Floppy disk adapter
Parallel port 1

System timer interrupt from timer 8254
Keyboard output buffer full