[sdiy] Polyphonic keyboard scanner

[David G. Dixon]

I know this will earn the scorn and derision of the programmers on the list,
but I'm wondering:  Does anyone here know of a polyphonic keyboard scanner
circuit based on logic IC's (non-programmable)?  Is this even feasible
without a massive pile of chips?  If so, I'd be very interested to learn
what the algorithm is.  The approaches I've been thinking about are all
fairly complicated (one scanner (counter + 2 multiplexers), but 8 separate
latches and ladders with data comparators to compare the count to the
latched data for preventing double latching and controlling note-off -- I
haven't worked out all the gory details yet).  I'd like to design something
that will send out 8 CV's, 8 triggers, and one gate.