Measurement Computing Personal488 rev.3.0 - Manual (Page 44)

4-4 Hardware Configuration Reference 04-09-01 Personal488 for Windows 95/98/Me/NT/2000
Configuring the AT488 Interface Interrupt (IRQ)
S 2
S 2
In te rru p t
L e ve l 1 0 In te rru p t
L e ve l 11 In te rru p t
L e ve l 1 2 In te rru p t
L e ve l 1 4 In te rru p t
L e ve l 1 5
IR Q
IR Q
3
4
5
6
7
9
1 0
11
1 2
1 4
1 5
3
4
5
6
7
9
1 0
11
1 2
1 4
1 5
In te rru pt
L ev e l 6 In te rru pt
L ev e l 9
A T 4 8 8 I n te rr u p t S e le c tio n s
1 2 3 4 1 2 3 4
1 2 3 4 1 2 3 4 1 2 3 4 1 2 3 4 1 2 3 4
O P E N O P E N
O P E N O P E N O P E N O P E N O P E N
In te rru p t
L e ve l 7
1 2 3 4
O P E N
In te rru pt
L ev e l 3 In te rru pt
L ev e l 4
1 2 3 4 1 2 3 4
O P E N O P E N
In te rru p t
L e ve l 5
1 2 3 4
O P E N
The factory default Interrupt (IRQ) is 5. If this creates a conflict, reset switch S2 and jumper IRQ
according to the figure. The switch and jumper settings must both indicate the same interrupt level
for correct operation with interrupts. If reset, record the new Interrupt (IRQ) being used.
The AT488 interface board may be set to interrupt the PC on the occurrence of certain hardware conditions.
The main board interrupt may be set to IRQ level 3 through 7, 9 through 12, 14, or 15. Interrupts 10
through 15 are only available in a 16-bit slot on an AT-class machine. Interrupt 9 becomes synonymous
with Interrupt 2 when used in a PC/XT bus.
The selected interrupt may be shared among several AT488s in the same PC/AT chassis. The AT488
adheres to the “AT-style” interrupt sharing conventions. When the AT488 requires service, the IRQ
jumper determines which PC interrupt level is triggered. When an interrupt occurs, the interrupting device
must be reset by writing to an I/O address which is different for each interrupt level. The switch settings
determine the I/O address to which the board’s interrupt rearm circuitry responds.