THere was an ap note for the phillips 8x??? (64 pin 8051 derivitive)
describing a printer buffer that drove dram from software that might
be applicable.  The 8051 did the address multiplexing, drove CAS and RAS
from software, and did software refresh...

I don't think the 16C84 has enough pins to make it easy, but the above
would make a reasonable start...

BillW