[Coco] new high density controller

[Mike Pepe]

I've got some Intel 82077 chips on their way. They seem simple to 
interface to a CoCo, and support 250,300,500, 1M and 2M transfer rates. 
You could run a 2.88MB floppy!

They also have a 16 byte FIFO. I'd think that would be enough such that 
it could be used as a no-halt controller without having to rig up a 
Disto-like buffering contraption.

My plan would be to use both a WD1773 and 82077 in the same physical 
controller attached to one set of drives. This would be 100% CoCo 
compatible until you enabled the 82077 with a driver.

If anyone's interested, or has input, let me know.

-Mike