Ziatech Corporation ZT 8809A, Руководство по эксплуатации

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Interrupt Controller (8259A)
INTERRUPT ASSIGNMENTS ON THE ZT 8809A
The PIC has eight interrupt inputs, IR0 through IR7. Figure 12-5
illustrates the interrupt options available on the ZT 8809A. Each
interrupt source is available at a wirewrap pin, and one of each pair of
wirewrap pins is jumper selected to drive the interrupt at the PIC. In
the figure, interrupt sources preceded by bullets are interrupts required
by STD DOS; do not change these if you use STD DOS on the
ZT 8809A. Refer to Appendix A for a description of jumpers W2-
W11.
If a particular interrupt source is desired to drive a particular interrupt
request level, you may wire-wrap it to that source if a simple jumper
selection is not available. Be sure to pay attention to the active level
of the source and whether STD DOS requires the use of that interrupt
level. If active low, that signal must be inverted before being routed to
the interrupt controller. Figure 12-5 illustrates the active levels of all
interrupts and where these sources are inverted, if necessary. An
asterisk after the signal name indicates active low. Factory default
assignments are indicated by a dagger (†). In summary, the interrupts
driven from the counter/timers and the serial and printer ports are
active high; all sources from the backplane and frontplane are active
low.
Note: Low true signals followed by an asterisk (*) are inverted on-
board before they drive the appropriate interrupt request input (IRx).
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