Specifications

Hardware Configuration
2–55
2.16.4 PCI Bus (P21) Notes
1. Signal M66EN is grounded on the motherboard (Ground = 33MHz bus speed).
2. The shaded cells in the table denote unsupported signals.
3. The KEY pins are to guarantee proper module installation. Pin-A1 will be removed and the female
side plugged for 5.0V I/O signals and Pin-D30 will be modified in the same manner for 3.3V I/O.
Both pins will be removed for 3.3/5.0 operation.
2.16.5 Interrupt and DMA Channel Usage
The PC architecture provides several interrupt and DMA control signals. When you expand the system
through the ISA portion of the PC/104-Plus bus (P1, P2) with MiniModule products or plug-in cards that
require either interrupt or DMA support, you must select which interrupt or DMA channel to use.
Typically this involves switches or jumpers on the expansion module. In most cases, these are not shared
resources. It is important that you configure the new module to use an interrupt or DMA channel not
already in use. For your convenience, Table 2–44 and Table 2–45 provide a summary of the normal
interrupt and DMA channel assignments on the Little Board/P5i.
The PCI bus uses four interrupts (INTA*, INTB*, INTC*, and INTD*). These interrupts are mapped to
any of the available ISA interrupts. The PCI bus needs only INTA* if each PCI device is single function.
If an expansion card has multiple functions, then more interrupts may be required.
Table 2–44 Interrupt Channel Assignments
Interrupt Function
IRQ0
IRQ1
IRQ2
IRQ3
IRQ4
IRQ5
IRQ6
IRQ7
ROM BIOS clock tick function, from Timer 0*
Keyboard interrupt*
Cascade input for IRQ8-15*
Serial 2
Serial 1
Available
Floppy controller
Parallel port (option)
IRQ8
IRQ9
IRQ10
IRQ11
IRQ12
IRQ13
IRQ14
IRQ15
Reserved for battery-backed clock alarm*
Available
Available
Available
Available
Reserved for coprocessor*
IDE hard disk controller 1
IDE hard disk controller 2