This is very similar to something I did a few years ago. I built a spectrum analyser with my SE/30. Basically, wrote a program to read serial data inputted from the atmel processor, the atmel processor was responsible for sampling the MSGEQ7 IC, and sending it to the Mac. 

It worked, but was slighly slow update/refresh on the mac side. To be expected because the app was written in realbasic. RB apps wont run on the 68000 because it requires CFM68K which is 32-bit.