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4 HP BIOS
BIOS Addresses
HP I/O Port Map (I/O Addresses Used by the System
1
)
Peripheral devices, accessory devices and system controllers are accessed
via the system I/O space, which is not located in system memory space. The
64 KB of addressable I/O space comprises 8-bit and 16-bit registers (called
I/O ports) located in the various system components. When installing an
accessory board, ensure that the I/O address space selected is in the free
area of the space reserved for accessory boards (100h to 3FFh).
Although the Setup program can be used to change some of the settings, the
following address map is not completely BIOS dependent, but is determined
partly by the operating system. Note that some of the I/O addresses are
allocated dynamically.
1. If configured.
I/O Address Ports Function
0000 - 000F DMA controller 1
0020 - 0021 Master interrupt controller (8259)
002E - 002F NS-317 Configuration registers
0040 - 0043 Timer 1
0060, 0064 Keyboard controller (reset, slow A20)
0061 Port B (speaker, NMI status and control)
0070 Bit 7: NMI mask register
0070 - 0071 RTC and CMOS data
0080 Manufacturing port (POST card)
0081 - 0083, 008F DMA low page register
0092 PS/2 reset and Fast A20
0096 - 0097 Little Ben
00A0 - 00A1 Slave interrupt controller
00C0 - 00DF DMA controller 2
00F0 - 00FF Co-processor error
0130 - 013F AD1816 sound system
0170 - 0177 IDE secondary channel
01F0 - 01F7 IDE primary channel
0200 - 0207 AD1816 Joystick port
0220 - 0232 AD1816 Soundblaster
0278 - 027F LPT 2
02E8 - 02EF Serial port 4 (COM4)
02F8 - 02FF Serial port 2 (COM2)
0372 - 0377 IDE secondary channel, secondary flexible disk drive