107
5 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).
1.If configured.
Default Values for
I/O Address Ports
Function
0000 - 000F
DMA controller 1
0020 - 0021
Master interrupt controller (8259)
002E - 002F
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
0080
Manufacturing port (POST card)
0081 - 0083, 008F
DMA low page register
0092
PS/2 reset and Fast A20
00A0 - 00A1
Slave interrupt controller
00C0 - 00DF
DMA controller 2
00F0 - 00FF
Co-processor error
0170 - 0177
Free (IDE secondary channel)
01F0 - 01F7
IDE primary channel
0278 - 027F
LPT 2
02E8 - 02EF
Serial port 4 (COM4)
02F8 - 02FF
Serial port 2 (COM2)
0372 - 0377
Free (IDE secondary channel, secondary floppy disk drive)
0378 - 037A
LPT1
03B0 - 03DF
VGA
03E8 - 03EF
COM3
03F0 - 03F5
Floppy disk drive controller
03F6
IDE primary channel
03F7
Floppy disk drive controller