Epson IR-320, Technical Reference Manual

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7-4 Hardware Specifications Rev. C
DMA
The IR-320 connects two 8237A-equivalent DMA controllers to support seven DMA channels.
Channels 0, 1, 2, and 3 provide 8-bit data transfers; channels 5, 6, and 7 provide 16-bit data
transfers. The IR-320 uses channel 2 for the floppy disk drive controller and releases the other
channels to the ISA bus. The following table lists the DMA channel allocation.
* When LPT1 is in ECP mode, use one of these channels.
System Interrupts
The system connects 2 8259A-equivalent interrupt controllers in cascade and has 15 levels of
interrupts, besides NMIs. The following table shows the application for each interrupt. Change
the system interrupts with the BIOS setup program or Plug & Play function.
*
1
PCI (for example, network) is automatically set through the detection of the unused interrupt level.
*
2
Changes are not possible when the device is in use, but can be cleared when not in use.
*
3
This can be set to “Not used” in the BIOS setup, but the IRQ is not released.
DMA channels
Controller Channel Application
DMA1 8 bits 0 (Spare)
1 (Spare*)
2 Floppy disk drive controller
3 (Spare*)
DMA2 16 bits 4 Controller 1 cascade
5 (Spare)
6 (Spare)
7 (Spare)
System interrupts
Controller 1 Controller 2 Application Changeable?
IRQ0 Timer NO
IRQ1 Keyboard NO
IRQ2 Controller 2 cascade NO
IRQ8 RTC NO
IRQ9 ACPI NO
IRQ10 Serial port 4 OK
IRQ11 Serial port 3 OK
IRQ12 Mouse OK
IRQ13 Numerical operation coprocessor NO
IRQ14 Hard disk controller (primary) *
2
IRQ15 Hard disk controller (secondary) *
2
IRQ3 Serial port 2 OK
IRQ4 Serial port 1 OK
IRQ5 Not used *
1
OK
IRQ6 Floppy disk controller NO *
3
IRQ7 Parallel port 1 OK
NMI I/O error check NO