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Personal488 for Windows 95/98/Me/NT/2000
04-09-01
Hardware Configuration Reference 4-3
AT488 Configurations
The I/O base address, IRQ, and DMA settings are switch/jumper selectable via the following locations on
the AT488 interface board: One 2-microswitch DIP switch labelled S1, one 4-microswitch DIP switch
labelled S2, two 14-pin headers labelled DACK and DRQ, and one 22-pin header labelled IRQ. The DIP
switch settings, and the arrangement of the jumpers on the headers set the hardware configuration.
For the next steps, make sure that the I/O address, IRQ, and DMA set on the interface board are different
from any existing ports in your system. A conflict results when two I/O addresses, IRQs, or DMAs are
the same. (As the exception, additional AT488 interfaces may share the same IRQ and DMA values.) If
there is a conflict, reconfigure the switch/jumper settings. Refer to the following figures as needed.
Configuring the AT488 Interface I/O Base Address
In te rrup t L e ve l 5
D M A 1 6-B it C h a nn e l 5
B a se A dd res s
0 2E 1 In te rrup t
L ev el 5
A T 4 8 8 D e fa u lt S e ttin g s
S 1
D A C K
D R Q
IR Q
S 2
A T 4 8 8 I /O B a se
A d d res s S ele c tio n s
S 1
4 2E 1 6 2E 1
2 2E 1 0 2E 1
5 6 7 0 1 2 3
3 4 5 6 7 9
10
11
12 14 15
O P E N O P E N O P E N
O P E N O P E N
1 2
1 2 1 2
1 2
1 2
1 2 3 4
O P E N
The factory default I/O base address is
02E1
. If this creates a conflict, reset switch S1 according to the
figure and following table. The register addresses will be automatically relocated at fixed offsets from the
base address. If reset, record the new Input/Output (I/O) address being used.
Selected I/O Base
Address
02E1 22E1 42E1 62E1
Register
Automatic Offset Addresses
Read Register Write Register
02E1 22E1 42E1 62E1 Data In Data Out
06E1 26E1 46E1 66E1 Interrupt Status 1 Interrupt Mask 1
0AE1 2AE1 4AE1 6AE1 Interrupt Status 2 Interrupt Mask 2
0EE1 2EE1 4EE1 6EE1 Serial Poll Status Serial Poll Mode
12E1 32E1 52E1 72E1 Address Status Address Mode
16E1 36E1 56E1 76E1 CMD Pass Through Auxiliary Mode
1AE1 3AE1 5AE1 7AE1 Address 0 Address 0/1
1EE1 3EE1 5EE1 7EE1 Address 1 End of String
The I/O base address sets the addresses used by the computer to communicate with the IEEE 488 interface
hardware on the board. The address is normally specified in hexadecimal and can be
02E1
,
22E1
,
42E1
, or
62E1
. The registers of the IOT7210 IEEE 488 controller chip and other auxiliary registers are then located
at fixed offsets from the base address.
Most versions of Driver488 are capable of managing as many as four IEEE 488 interfaces. To do so, the
interface configurations must be arranged to avoid conflict amongst themselves. No two boards may have
the same I/O address; but they may, and usually should, have the same DMA channel and interrupt level.