I/O Port Address Map; Dma Channels - TMC TI6NBF+ User Manual

3.5 I/O Port Address Map

Each peripheral device in the system is assigned a set of I/O port
addresses which also becomes the identity of the device. There is a total
of 1K port address space available. The following table lists the I/O port
addresses used on the motherboard.
Address Device Description
000h - 01Fh DMA Controller #1
020h - 03Fh Interrupt Controller #1
040h - 05Fh Timer
060h - 06Fh Keyboard Controller
070h - 07Fh Real Time Clock,, NMI
080h - 09Fh DMA Page Register
0A0h - 0BFh Interrupt Controller #2
0C0h - 0DFh DMA Controller #2
0F0h Clear Math Coprocessor Busy Signal
0F1h Reset Math Coprocessor
1F0h - 1F7h IDE Interface
2F8h - 2FFh Serial Port #2(COM2)
378h - 3FFh Parallel Port #1(LPT1)
3F0h - 3F7h Floppy Disk Controller
3F8h - 3FFh Serial Port #1(COM1)

3.6 DMA Channels

There are seven DMA channels available on the motherboard; only
DMA2 is used by the floppy controller. In the case that ECP mode on the
parallel port is utilized, DMA1 or DMA3 will be used.
TI6NBF+ Pentium II /III ATX Motherboard User's Manual
Chapter 3 Hardware Description
9