Ampro Corporation 486E - Manual (Page 28)

Little Board™/486e Technical Manual
2–12
Interrupt Assignments
Interrupt 4 (IRQ4) is assigned to Serial 1 and Interrupt 3 (IRQ3) to Serial 2. These assignments
can be disabled, but they cannot be changed. Serial 3 and Serial 4 can share their interrupts, using
a “wired-or” configuration, they can use independent IRQs, or they can be disabled and use no
interrupt at all. Jumper options are provided to independently select the wired-or configuration or
independent interrupts for Serial 3 and Serial 4. See Figure 2–3 through 2–5.
Figure 2–3. Shared Wired-Or Configuration
Figure 2–4. Serial 3 Interrupt Configuration (W8)
Figure 2–5. Serial 4 Interrupt Configuration (W9)
When a serial port is disabled, its IRQ is available to other peripherals installed on the PC/104
expansion bus.
Shared W7 Non-Shared
IRQ11 W8 IRQ7
IRQ10 W9 IRQ5