I/O Port Address

The factory-set I/O port addresses for the server are assigned as follows:

Address

Chip in Use

00 - 1F

8-bit DMA control register

 

 

20 - 21

Master 8259 programming interface

 

 

2E - 2F

Configuration

 

 

40 - 43

8254 programming interface

 

 

60

Keyboard & mouse

 

 

61

NMI status register

 

 

64

Keyboard & mouse

 

 

70 - 71

NMI enable register/real-time clock

 

 

80 - 8F

16-bit DMA control register

 

 

A0 - A1

Slave 8259 programming interface

 

 

C0 - DF

DMA controller page register

 

 

E0 - E9

Base address register

 

 

F0

Register IRQ13

 

 

F1 - FF

Logical device configuration

 

 

170 - 177 or BAR2

EDMA2-compatible mode primary command block register

 

 

1F0 - 1F7 or BAR0

EDMA2-compatible mode secondary command block register

 

 

278 - 27F

(Parallel port 3)

 

 

2F8 - 2FF

Serial port 2

 

 

BAR or 376

EDMA2-compatible mode secondary command block register

 

 

370 - 377

(Floppy disk drive 2), IDE 2

 

 

378 -37F

(Parallel port 2)

 

 

3B0 - 3BB

VGA

 

 

3BC - 3BE

Parallel port 1

 

 

3C0 - 3DF

VGA

 

 

3F6 or BAR1

EDMA2-compatible mode primary command block register

 

 

3F0 - 3F7

Floppy disk drive 1, IDE 1

 

 

3F8 - 3FF

Serial port 1

 

 

40B

DMA1 expansion write mode register

 

 

4D0

Master 8259 ELCR programming

 

 

4D1

Slave 8259 ELCR programming

 

 

4D6

DMA2 expansion write mode register

 

 

580 - 58F

SMBus control

 

 

IRQ and I/O Port Addresses C-3

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NEC 120Lg manual IRQ and I/O Port Addresses C-3, Address Chip in Use