RS422I-PA Manual
Page 4-2
Manual 00650-519-1
I/O bus address switches are marked A3-A9. The following table lists switch label vs. the address
line controlled and the relative weights of each.
Address Switch Settings
1st Digit
2nd Digit
3rd
Switch Label
7
6
5
4
3
2
1
Address Line Controlled
A9
A8
A7
A6
A5
A4
A3
Decimal Weight
512
256
128
64
32
16
8
Hexadecimal Weight
200
100
80
40
20
10
8
Table 4-2:
Address Switch Setup
In order to read the address switch setup, assign a binary "1" to switches that are turned OFF and a
binary "0" to switches in the ON position. For example, as illustrated in the following table,
switch selection corresponds to binary 10 1101 1xxx (hex 2D8). The "xxx" represents address
lines A2, A1, and A0 used on the card to select individual registers. See Chapter 5, Programming
in this manual.
Switch Label
A9
A8
A7
A6
A5
A4
A3
Setup
OFF
ON
OFF
OFF
ON
OFF
OFF
Binary Representation
1
0
1
1
0
1
1
Conversion Factors
2
1
8
4
2
1
8
HEX Representation
2
D
8
Table 4-3:
Example Address Setup
Review the Address Selection Table carefully before selecting the card address. If the addresses of
two installed functions overlap you will experience unpredictable computer behavior.
The following table lists standard DOS COM Port addresses.
Serial
COM Port
IRQ
Base Hex
Address
Address Switch Settings
A9 A8 A7 A6 A5 A4 A3
COM1
IRQ 4
3F8
1
1
1
1
1
1
1
COM2
IRQ 3
2F8
1
0
1
1
1
1
1
COM3
IRQ 4
3E8
1
1
1
1
1
0
1
COM4
IRQ 3
2E8
1
0
1
1
1
0
1
Table 4-4:
Standard DOS COM Port Addresses
Notice that only two interrupts are assigned to four serial ports. "Sharing" interrupts is not a good
idea if both ports are used at the same time.