User`s guide

Expansion cards
FT1200 OWNER’S HANDBOOK 4/3
Do not
disable either one unless you have no intention of using the
affected port. Similarly, if you have no intention of using the
parallel port, you can disable it with the BIOS Setup utility,
completely freeing IRQ7 for use by an expansion card.
Direct memory access (DMA) channel
Some hardware devices can use a DMA channel to access system
memory without directly burdening the processor. Computers have
DMA channels numbered DMA0 to DMA7. The following table
gives details of which ones may be available:
DMA Default assignment Available?
DMA0 Yes
DMA1 Default (8 bit) Audio Optionally
DMA2 Diskette/floppy disk controller No
DMA3 Enhanced Capabilities Port (default) Optionally
DMA4 System No
DMA5 Default (16 bit) Audio Optionally
DMA6 Yes
DMA7 Yes
Base input/output (I/O) port address
I/O ports are used by the processor to communicate with hardware
devices. Some expansion cards are also controlled by I/O ports. The
base I/O port address specifies where the card’s ports begin. The
following table lists the I/O ports used by devices on the
motherboard. Any ports not listed below may be available for an
expansion card. This extensive list continues on the next page.
I/O ports Default assignment
000h-01Fh DMA controller 1
020h-021h Interrupt controller 1
034h, 038h, 03Ch Alternate Local bus ATA/IDE
040h-05Fh System timer
060h-06Fh Keyboard controller
070h-07Fh Real-time clock, NMI mask