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Chapter 4 System Support
Compaq Deskpro EN Series of Personal Computers
Desktop and Minitower Form Factors
Third Edition - September 1998
4-46
4.7 I/O MAP AND REGISTER ACCESSING
4.7.1 SYSTEM I/O MAP
Table 4–19.
System I/O Map
Table 4-19.
System I/O Map
I/O Port Function
0000..000Fh DMA Controller 1
0020..0021h Interrupt Controller 1
0040..0043h Timer 1
0060h Keyboard Controller Data Byte
0061h NMI, Speaker Control
0064h Keyboard Controller Command/Status Byte
0070h NMI Enable, RTC/Lower CMOS Index
0071h RTC Data
0078h-007Bh GPIO Port 1 Control (87307 I/O controller)
007Ch-007Fh GPIO Port 2 Control (87307 I/O controller)
0080..008Fh DMA Page Registers
0092h Port A, Fast A20/Reset
00A0..00A1h Interrupt Controller 2
00B2h, 00B3h APM Control/Status Ports
00C0..00DFh DMA Controller 2
00F0h Math Coprocessor Busy Clear
015C, 015Dh 87307 I/O Controller Configuration Registers (Index, Data)
0170..0177h Hard Drive (IDE) Controller 2
01F0..01FFh Hard Drive (IDE) Controller 1
0201..024Fh Audio subsystem control (primary & secondary addresses)
0278..027Bh Parallel Port (LPT2)
02F8..02FFh Serial Port (COM2)
0371.. 0375h Diskette Drive Controller Alternate Addresses
0376h IDE Controller Alternate Address
0377h IDE Controller Alternate Address, Diskette Drive Controller Alternate Address
0378..037Fh Parallel Port (LPT1)
0388..038Bh FM synthesizer (alias addresses)
03B0..03DFh Graphics Controller
03E8..03EFh Serial Port (COM3)
03F0..03F5h Diskette Drive Controller Primary Addresses
03F6, 03F7h Diskette Drive Controller Primary Addresses, Hard Drive Controller Primary Addresses
03F8..03FFh Serial Port (COM1)
04D0, 04D1h Master, Slave Edge/Level INTR Control Register
0C00, 0C01h PCI IRQ Mapping Index, Data
0C06, 0C07h Reserved - Compaq proprietary use only
0C50, 0C51h System Management Configuration Registers (Index, Data)
0C52h General Purpose Port
0C7Ch Machine ID
0CF8h PCI Configuration Address (dword access)
0CF9h Reset Control Register
0CFCh PCI Configuration Data (byte, word, or dword access)
FF00..FF07h IDE Bus Master Register
NOTE: Assume unmarked gaps are reserved/unused.