Pointing Device Interface Operation; Keyboard/Pointing Device Interface Programming - Compaq Deskpro EXS Technical Reference Manual

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.

5.6.3 KEYBOARD/POINTING DEVICE INTERFACE PROGRAMMING

Programming the keyboard interface consists of configuration, which occurs during POST, and
control, which occurs during runtime.
5.6.3.1 8042 Configuration
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
Index
Address Function
30h Activate
70h Primary Interrupt Select
72h Secondary Interrupt Select
F0h Reset and A20 Select
5-18 Compaq Deskpro EXS and Workstation 300 Personal Computers
Featuring the Intel Pentium 4 Processor
Table 5-14.
First Edition – December 2000
R/W
R/W
R/W
R/W
R/W