American Megatrends 16 Series, User Manual

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American Megatrends Enterprise-II Motherboard User's Guide
5
Description,
Continued
Seven DMA Channels
The Enterprise-II has seven DMA channels.
In accordance with the EISA
specifications, any DMA channel may be
programmed for 8, 16, or 32-bit DMA device
size and ISA compatible, type A, type B,
or burst type C modes.
Fifteen Interrupt Levels
The Enterprise-II has 15 hardware
interrupt levels. Of course, NMIs take
precedence over the following hardware
interrupts.
Priority Label Typical Interrupt Source
1 IRQ 0 Interval Timer 1, Counter 0 OUT
2 IRQ 1 Keyboard
3-10 IRQ 2 Used internally for IRQ 8 through IRQ 15
3 IRQ 8 Real-TIme-Clock
4 IRQ 9 EISA bus
5 IRQ 10 EISA bus
6 IRQ 11 EISA bus
7 IRQ 12 Mouse on EISA bus
8 IRQ 13 Coprocessor Error
9 IRQ 14 EISA bus (Hard disk drive controller)
10 IRQ 15 EISA bus
11 IRQ 3 EISA bus (Serial Port 2)
12 IRQ 4 EISA bus (Serial Port 1)
13 IRQ 5 EISA bus (Parallel Port 2)
14 IRQ 6 EISA bus and floppy disk controller
15 IRQ 7 EISA bus (Parallel Port 1)