User manual

BIOS Setup
- 34 - EC3-1816CLD2NA(B)
3.4 System Resource Managed by UEFI under X86 Platform
We define three kinds of system resources here: I/O port address, IRQ interrupt
number and DMA number.
 DMA
Level Function
DMA0 Unassigned
DMA1 Unassigned
DMA2 Unassigned
DMA3 Unassigned
DMA4 Used for DMAC cascade
DMA5 Unassigned
DMA6 Unassigned
DMA7 Unassigned
 APIC
Advanced programmable interrupt controller. Most motherboards above P4
level support APIC and provide more than 16 interrupt sources, like IRQ16 - IRQ23;
while some others can have up to 28 interrupt sources, such as motherboard
supporting PCI-X. However, relevant OS are required to enable that function.
 IO Port Address
Only 16 IO address lines are designed for X86, from 0 ~ 0FFFFh; there is 64K
for the system I/O address space. In traditional ISA connector, only the foregoing
1024 (0000 ~ 03FFh) are adopted while the ports above 0400h are adopted by PCI
and EISA connectors. Each peripheral will occupy portion of the space. The table
below shows the I/O connectors used in X86 platform: