Apple II parallel cards (Apple Inc. brand) have the ability to 
produce interrupts.  
_______________
| | | | | | | | 
|1|2|3|4|5|6|7|   switch 7 controls interrupts.  with it in the ON
| | | | | | | |   position, interrupts are enabled.
---------------

SLOT            1      2      3      4      5      6      7 
--------------------------------------------------------------
Enable  IRQ  -16234 -16218 -16202 -16186 -16170 -16154 -16138
($C086+s0) 
--------------------------------------------------------------
Disable IRQ  -16233 -16217 -16201 -16185 -16169 -16153 -16137   
& autostrobe
($C087+s0)
--------------------------------------------------------------

An acquaintance (Bob R.) just sent me a multi program switcher 
for the Apple II similar to ExtraK.  I loaded it into WOZBOTS 
drive and he now runs around the house with multiple programs 
in memory (speech software in one bank, mapping software in
another, etc)

It would be neat to make a programmable interrupt generator
for the parallel card so he can automatically switch between
programs and check sensors on interrupts.  Send the circuit
a time (8bits) and it would generate an interrupt once each
time period.