Specifications

Interrupts and

DMA Channels

Interrupts

The assignment of interrupts for the EPC-8A is shown in the following table:

DMA Channels

The assignment of DMA channels for the EPC-8A is shown in the following table.

Table B-1. Interrupts

Interrupt Description

NMI DRAM parity error, EXM expansion interface I/O channel check

IRQ0 Timer

IRQ1 Keyboard

IRQ2 IRQ8–IRQ15 cascade through IRQ2

IRQ3 COM2 serial port

IRQ4 COM1 serial port

IRQ5 Unassigned

IRQ6 Usually needed for floppy disk controller

IRQ7 LPT1 parallel port

IRQ8 Real-time clock

IRQ9 Unassigned

IRQ10 VME interrupt/event

IRQ11 Unassigned

IRQ12 Unavailable (you must use external keyboard option to free IRQ12.)

IRQ13 Coprocessor

IRQ14 IDE disk controller

IRQ15 Unassigned

Table B-2. DMA Channels

Channel Description

0 Unassigned (8-bit)

1 Unassigned (8-bit)

2 Usually needed for floppy disk (8-bit)

3 Usually needed for SCSI disk (8-bit)

4 (Channel 0–Channel 3 cascade through Channel 4)

5 Unassigned (16-bit)

6 Unassigned (16-bit)

7 Unassigned—not connected to EXM expansion interface (16-bit)

Appendix B