Epson DM-M820, Техническое справочное руководство, Страница: 44 / 324

3-2 Hardware Specifications Rev. I
DMA
The IM-800 supports seven DMA channels. Channels 0, 1, 2, and 3 provide 8-bit data transfers;
channels 4, 5, 6, and 7 provide 16-bit data transfers. The IM-800 uses channel 2 for the floppy
disk drive controller and releases the other channels to the other devices. 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. If Serial port 3/
4 is used with Windows, use an unused interrupt level. If Serial port 3/4 is used with DOS, Serial port 3 is set to IRQ11
and Serial port 4 is set to IRQ10 automatically.
*
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 Not used *
1
OK
IRQ10 Not used *1 OK
IRQ11 Not used *
1
OK
IRQ12 Mouse NO
IRQ13 Numerical operation coprocessor NO
IRQ14 IDE controller (primary) *
2
IRQ15 IDE 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