Compaq W4000 Manual De Usuario

Technical Reference Guide 

 

 

This chapter describes the standard (i.e., system board) interfaces that provide input and output 
(I/O) porting of data and specifically discusses interfaces that are controlled through I/O-mapped 
registers. The following I/O interfaces are covered in this chapter:  
 
♦  Enhanced IDE interface (5.2)   

 

page 5-1 

♦  Diskette drive interface (5.3)   

 

page 5-4 

♦  Serial 

interfaces 

(5.4) 

   page 

5-8 

♦  Parallel interface (5.5) 

 

 

page 5-11 

♦  Keyboard/pointing device interface (5.6) 

page 5-16 

♦  Universal serial bus interface (5.7) 

 

page 5-22 

♦  Audio subsystem (5.8) 

 

 

page 5-26 

♦  Network interface controller (5.9) 

 

page 5-32 

 
 

 
The enhanced IDE (EIDE) interface consists of primary and secondary controllers integrated into 
the 82801 ICH2 component of the chipset. Two 40-pin IDE connectors (one for each controller) 
are included on the system board. Each controller can be configured independently for the 
following modes of operation:  
 
♦ 

♦ 

♦ 

Programmed I/O (PIO) mode – CPU controls drive transactions through standard I/O mapped 
registers of the IDE drive. 
8237 DMA mode – CPU offloads drive transactions using DMA protocol with transfer rates 
up to 16 MB/s. 
Ultra ATA/100 mode – Preferred bus mastering source-synchronous protocol providing 
transfer rates of 100 MB/s. 

 

NOTE: These systems include 80-conductor data cables required for UATA/66 and /100 
modes. 

 

 

The IDE interface is configured as a PCI device during POST and controlled through I/O-mapped 
registers at runtime. 

 

 

 

5-1