The current way I have it set up it I have an Arduino sending serialized data to a VIA that the 65c02 reads from. The way I have the VIA setup, I have to rotate the actual serial bit (several times) that comes in and then reconstruct the byte in the 65c02's RAM. I was hoping I could use two ACIAs to accept the serial data and reconstruct the byte and then send the byte itself back to the 65c02 - hardware faster than software, I'm hoping, and I can set the baud rate so I don't have to deal with the Arduino sending bits up to 16x faster than the current speed of my 65c02.
I'm new at this, so it might be completely wrong!