Measurement Computing Alpha488 - Manual (Page 4)

Alpha488
2 419-0920 Rev. 1.0, 7/96
Figure 1. Alpha488 I/O Base Address Settings
Interrupt Selection
The main board interrupt may be set to IRQ level 3 through 7, 10, 11, 12, 14, or 15.
When the Alpha488 requires service, the IRQ jumper determines which 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. The IRQ jumper and
switch settings must both indicate the same interrupt level for correct operation with
interrupts. Figure 2 shows the settings for selected interrupts.