DELL 4200 User Manual

System Overview

1-23

IRQ6 

Generated by super I/O controller to indicate that diskette drive 
requires service

IRQ7 

Generated by super I/O controller to indicate that device con-
nected to parallel port requires service

IRQ8

Generated by keyboard controller for each tick of RTC

IRQ9 

Available for use by expansion card

IRQ10

Available for use by expansion card

IRQ11

Available for use by expansion card

IRQ12 

Generated by keyboard controller to indicate that mouse’s output 
buffer is full

IRQ13 

Generated by math coprocessor to indicate coprocessor error

IRQ14 

Available for use by expansion card

IRQ15

Available for use by expansion card

DREQ0

Available

DREQ1

Available

DREQ2

Generated by super I/O controller to initiate DMA cycle for 
attached diskette drive

DREQ3

Available

DREQ4

Generated by bus controller chip to activate second DMA 
controller

DREQ5

Available

DREQ6

Available

DREQ7

Available

Table 1-3.  Interrupt Assignments (continued)