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PA 7400
Technical description Chapter 5
18
5.3 Base address
WARNING!
If the base address set is wrong, the board and/or the PC may be
destroyed.
Before installing the board
Check
, that
- the base address is free
- the address range required by the board is not already used by the PC or by
boards already installed in the PC.
Possible settings of the base address (see also "Jumper settings")
•
COM1-COM4
serial port 1
serial port 2
•
COM1-COM4 or
serial ports 1 and 2 (option 2S).
any other address
•
LPT1-LPT3
IMPORTANT!
Find out
which serial and parallel ports are already used by your PC.
•
Load
the DEBUG program.
Are recognised:
COM1, COM2, LPT1, LPT2 for DOS 3.3 and
COM1-COM4, LPT1-LPT2 for >DOS 4.0
Enter
On the screen
Meaning
C:>
debug <return>
-
d40:0 <return>
F8 03 F8 02 00 00 00 00 -78 03
'address 03F8 = COM1
´address 02F8 = COM2
´address 0378 = LPT1
q <return>
COM1 = 03F8, COM2 = 02F8, LPT1=0378 are used in this example by the PC.
You can set the base address of the serial ports through the block DIP switches
(Option 2S). In this case the jumpers J28, J27 and J26, J25 are not to be set for
the serial ports 1 and 2.
Address ranges
•
Make sure
that the address ranges of the serial ports do not overlap.
Decoding of the base addresses
The base addresses of serial ports 1 and 2 are decoded each in steps 8 bytes.