I had previously and briefly mentioned the hybrid aspect of the interfacing BUS for the Brain and this has now evolved through various testing trial and error into something more usable. The hybrid BBB is based on the proponent idea in the AM Algorithm Machine's Hybrid Bus, although it used a tiny 6-bit parallel version. For example, a two wire serial full duplex interface can use one wire or two wires just by changing the software. That's the idea. So we just put on the parallel bus and tweak software for three interfaces, i.e. make an 8-bit parallel and recycle 1 or 2 wires for serial duplex modes. The Hybrid BBB is a nice little hobby invention for getting more use out of a simple machine and increasing programming flexibility and minimizing the number of wired processor pins. It will also allow a system to be up and running sooner and leave the more complicated configurations for later. No schematics at this time for the Brain but there is a direct-connect schematic for the AM.
the AM Machine Interface
This versatile machine operates in four modes, which can be wired as single mode A, single mode B, or dual modes A & B, or simply C mode. Operate the AM using a single wire and serial PBASIC code commands or program the machine using the seven parallel port bits.
A - Single Wire Serial P0
B - Parallel Bus P3, P4, P5, P6, P7
A + B Dual BUS, as seen above
C - Parallel Bus Only P0, P3. P4, P5, P6, P7