MOTM

Your 320 can make a A / R EG with a trigger input only.

Keyboard trigger in to sync in of 320 set at relatively low frequency. 
Sine (or other output) to filter or something.  I used the 320 sine output
to the 420 filter FM1 set to minus 5.  The rate and shape controls shape
your A and R and the 320 impersonates an EG.  Of course if you hold the key
down for too long, your AR EG recycles...  But for those medium to quick
snappy envelopes, it is cool and gives you a lot of different slopes.

Depending on which wave you use from the 320 and how you have the shape
set, you may have to invert the output to have the right EG polarity. 
That's why the 420 FM input was so attractive a place to try it.

So, now that I have pointed out two new uses for a 320 (sub osc with shape
and AR EG), I would like to hear from others.  This thing has to have 1000
uses.  Let the patching begin.

Larry H