Chapter 4 System Support
Compaq Deskpro Personal Computers
Third Edition – April 2001
4-38
4.8 REGISTER MAP AND MISCELLANEOUS FUNCTIONS
This section contains the system I/O map and information on general-purpose functions of the
ICH2 and I/O controller.
4.8.1 SYSTEM I/O MAP
Table 4-17 lists the fixed addresses of the input/output (I/O) ports.
Table 4-17. System I/O Map
Table 4-17.
System I/O Map
I/O Port  Function 
0000..001Fh DMA Controller 1 
0020..002Dh  Interrupt Controller 1 
002E, 002Fh  Index, Data Ports to LPC47B357 I/O Controller (primary) 
0030..003Dh Interrupt Controller 
0040..0042h  Timer 1 
004E, 004Fh  Index, Data Ports to LPC47B357 I/O Controller (secondary) 
0050..0052h  Timer / Counter 
0060..0067h  Microcontroller, NMI Controller (alternating addresses) 
0070..0077h RTC Controller 
0080..0091h DMA Controller 
0092h  Port A, Fast A20/Reset Generator 
0093..009Fh DMA Controller 
00A0..00B1h   Interrupt Controller 2 
00B2h, 00B3h  APM Control/Status Ports 
00B4..00BDh Interrupt Controller 
00C0..00DFh  DMA Controller 2 
00F0h Coprocessor error register 
0170..0177h  IDE Controller 2 (active only if standard I/O space is enabled for primary drive) 
01F0..01F7h  IDE Controller 1 (active only if standard I/O space is enabled for secondary drive) 
0278..027Fh  Parallel Port (LPT2) 
02E8..02EFh  Serial Port (COM4) 
02F8..02FFh  Serial Port (COM2) 
0370..0377h  Diskette Drive Controller Secondary Address 
0376h  IDE Controller 2 (active only if standard I/O space is enabled for primary drive) 
0378..037Fh  Parallel Port (LPT1) 
03B0..03DFh Graphics Controller 
03BC..03BEh  Parallel Port (LPT3) 
03E8..03EFh  Serial Port (COM3) 
03F0..03F5h  Diskette Drive Controller Primary Addresses 
03F6h  IDE Controller 1 (active only if standard I/O space is enabled for sec. drive) 
03F8..03FFh  Serial Port (COM1) 
04D0, 04D1h  Interrupt Controller 
0678..067Fh  Parallel Port (LPT2) 
0778..077Fh  Parallel Port (LPT1) 
07BC..07BEh  Parallel Port (LPT3) 
0CF8h  PCI Configuration Address (dword access only ) 
0CF9h  Reset Control Register 
0CFCh  PCI Configuration Data (byte, word, or dword access) 
NOTE:   
Assume unmarked gaps are unused, reserved, or used by functions that employ variable I/O  
address mapping. Some ranges may include reserved addresses.