Chapter 4  System Support
 
Compaq Deskpro 4000 and 6000 Personal Computers
      featuring the Pentium II Processor
First Edition - October 1997
4-44
4.7.2  87307 I/O CONTROLLER CONFIGURATION
The 87307 I/O controller contains various functions such as the keyboard/mouse interfaces,
diskette interface, serial interfaces, and parallel interface. While the control of these interfaces
uses standard AT-type I/O addressing, the configuration of these functions uses indexed ports
unique to the 87307. In this system, hardware strapping selects I/O addresses 015Ch and 015Dh
at reset as the Index/Data ports for accessing the logical devices within the 87307. The hardware
strapping also places the 87307 into PnP motherboard mode.  The integrated logical devices are
listed as follows:
Table 4-20 lists the PnP standard control registers for the 87307.
Table 4–20. 
87307 I/O Controller PnP Standard Control Registers
   Table 4-20.
                    87307 I/O Controller PnP Standard Control Registers
Index Function Reset Value
00h Set RD_DATA Port 00h
01h Serial Isolation
02h Configuration Control
03h Wake (CSN) 00h
04h Resource Data
05h Status
06h Card Select Number (CSN) 00h
07h Logical Device Select:
   00h = 8042 Controller (Keyboard I/F)
   01h = 8042 Controller (Mouse I/F)
   02h = RTC/APC Configuration
   03h = Diskette Controller
   04h = Parallel Port
   05h = UART 2 (Serial Port B / IrDA)
   06h = UART 1 (Serial Port A)
   07h = GPIO Ports
   08h = Power Management
00h
20h Super I/O ID Register (SID) A0h
21h SIO Configuration 1 Register 16h
22h SIO Configuration 1 Register 02h
23h Programmable Chip Select Configuration Index 00h
24h Programmable Chip Select Configuration Data 00h
NOTE:
For a detailed description of registers refer to appropriate National documentation.
The configuration registers are accessed by writing the appropriate logical device’s  number to
index 07h and writing the desired offset to the index register. The data is then either written to or
read from the data register.