Aaeon PCM-4330 Instructions Manual page 71

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.
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.
LOWARD
PWR
Bit Name
7 - 1 SA7 - SA1
0 REGEN
HIGHADR RES
PWR
Bit Name
7 - 2 RES
1 - 0 SA9 - SA8
SA7 SA6 SA5
0 0 0
w w w
D7 D6 D5
Function
Address bits SA7 - SA1 of base address
Enable AAEON Feature Port
0 =
2 =
RES RES
x x x
x x x
D7 D6 D5
Font
(reserved)
Address bits SA9 - SA8 of base address
SA4 SA3 SA2
0 0 0
w w w
D4 D3 D2
AAEON Feature Port off
AAEON Feature Port on
RES RES RES
x x x
x x x
D4 D3 D2
SA1 REGEN
0 0
w w
D1 D0
SA9 SA8
x x
w w
D1 D0