Compaq W4000 Manual De Usuario

Chapter 5  Input/Output Interfaces 

 

5.6.2  POINTING DEVICE INTERFACE OPERATION 

 
The pointing device  (typically a mouse) connects to a 6-pin DIN-type connector that is identical 
to the keyboard connector both physically and electrically. The operation of the interface (clock 
and data signal control) is the same as for the keyboard. The pointing device interface uses the  
IRQ12 interrupt. 
 
 

 

Programming the keyboard interface consists of configuration, which occurs during POST, and 
control, which occurs during runtime. 

 
The keyboard/pointing device interface must be enabled and configured for a particular speed 
before it can be used. Enabling and speed parameters of the 8042 logic are affected through the 
PnP configuration registers of the LPC47B357 I/O controller. Enabling and speed control are 
automatically set by the BIOS during POST but can also be accomplished with the Setup utility 
and other software. 
 
 
The keyboard interface configuration registers are listed in the following table: 
 
Table 5–14.   Keyboard Interface Configuration Registers 
 

 

 

 

      

 Keyboard Interface Configuration Registers 

30h Activate 

R/W  

70h 

Primary Interrupt Select 

R/W 

 

72h 

Secondary Interrupt Select 

R/W 

 

F0h 

Reset and A20 Select 

R/W 

 

 

 
 
 
 
 
 
 
 
 
 
 
 
 
 
 

5-18   Compaq Evo and Workstation Personal Computers 
          Featuring the Intel Pentium 4 Processor