X hits on this document

33 views

0 shares

0 downloads

0 comments

11 / 15

136

PC Interfacing, Communications and Windows Programming

ISA

SD[15:0] IOCS16# MEMCS16# MEMR# MEMW# AEN IOCHRDY IOCHK# SYSCLK BALE IOR# IOW# SMEMR# SMEMW# 0WS# SA[7:0]

PIIX3

M U X

DD12/SBHE# DD[11:0]/SA[19:8] LA23/CS16 LA22/CS3S LA21/CS1P LA20/CS3P LA[19:17]/DA[2:0]

IDE

DIOR# DIOW# DDRQ[1:0] DDAK[1:0]# IORDY SOE# SDIR DD13

Figure 11.7

IDE/ISA interface with PIIX3.

DMA

DREQ[7:5,3:0] DACK[7:5,3:0] TC REFRESH#

PIIX3

Figure 11.8

DMA interface.

11.12 Interval timer

The PIIX3 contains three 8251-compatible counters which are contained in one PIIX3 timer unit, referred to as Timer-1. The 14.21818 MHz counters normally use OSC as a clock source. Each counter provides an essential system function, such as:

  • Counter 0, which connects to the IRQ0 line and provides a system timer interrupt for

a time-of-day, diskette time-out, and so on.

  • Counter 1, which generates a refresh request signal.

  • Counter 2, which generates the speaker tone.

Document info
Document views33
Page views33
Page last viewedMon Dec 05 23:22:45 UTC 2016
Pages15
Paragraphs1354
Words5176

Comments