Specifications

AAEON Feature Port

This port was introduced by AAEON to realize special functions of thePCM-4330

single board computer.

Feature port functions are also available through BIOS calls. These calls pro-

vide a save and convenient method to use AAEON feature port features. You

should use these BIOS calls whenever possible.

Incorrect arguments for direct port calls might lead to unexpected

behavior, system crashes or halts, render the system inoperative

or even damage components. Please study this section closely and

observe all notes as well as programming guidelines set fourth in

the component data sheets and documentation.

Setting the Base Address

To write to or read from the data on index port, the base address must be set first.

Setting the base address is done by a Word-OUT to port address 90h. Programming

can also be done with Byte-OUTs.

5.6.1

Port 90h Data Port Description

LOWARD SA7 SA6 SA5 SA4 SA3 SA2 SA1 REGEN

PWR 0 0 0 0 0 0 0 0

w w w w w w w w

D7 D6 D5 D4 D3 D2 D1 D0

Port 91h Data Port Description

HIGHADR RES RES RES RES RES RES SA9 SA8

PWR x x x x x x x x

x x x x x x w w

D7 D6 D5 D4 D3 D2 D1 D0

5.6

Bit Name Function

7 - 1 SA7 - SA1 Address bits SA7 - SA1 of base address

0 REGEN Enable AAEON Feature Port

0 = AAEON Feature Port off

2 = AAEON Feature Port on

Bit Name Font

7 - 2 RES (reserved)

1 - 0 SA9 - SA8 Address bits SA9 - SA8 of base address