Omega OMB-PER-488/W95, User Manual

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18 Personal488/AT (with AT488) Personal488 User's Manual For Windows95 and Windows NT
Step 3: Configuring the AT488 Interface Interrupt (IRQ)
1. The factory default Interrupt (IRQ) is 7. 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.
2. 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.