Specifications

Chapter 3 Hardware
LittleBoard 800 Reference Manual 23
Interrupt Channel Assignments
The channel interrupt assignments are shown in Table 3-1.
Table 3-1. Interrupt Channel Assignments
Device vs IRQ No. 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15
Timer
X
Keyboard
X
Secondary
Cascade
X
COM1
OO
D
OOO OOO O O O
COM2
O
D
OOOO OOO O O O
COM3
O OOOOO OO
D
OOO
COM4
O OOOOO O
D
OO OO
Floppy
X
Parallel
O OOOO
D
OOO O O O
RTC
X
IDE Primary
X
IDE Secondary
X
Math Coprocessor
X
PS/2 Mouse
X
PCI INTA
OOO
D
OO OO O O O O
PCI INTB
O OOOOO
D
OO O O O
PCI INTC
OOO
D
OO OO O O O O
PCI INTD
O OOOOO
D
OO O O O
PCI INTE
OOO
D
OO OO O O O O
PCI INTF
O OOOOO
D
OO O O O
PCI INTH
OOO
D
OO OO O O O O
Legend: D = Default, O = Optional, X = Fixed
NOTE The IRQs for the Ethernet, Video, and Internal Local Bus (ISA) are
automatically assigned by the BIOS Plug and Play logic. Local IRQs
assigned during initialization can not be used by external devices.
Memory Map
The following table provides the common PC/AT memory allocations. Memory below 000500h is used
by the BIOS.