I am showing progress on a new Game Plan MPU design early. The board is designed and the prototype built, but much testing must be done to be complete it.
I am calling it MPU-3. I am open to obtaining a license from Game Plan, but have not discussed it with them.
If licensing is arranged, I may be able to pre-burn a 2764 and include it ready to go.
It is meant to be very user friendly.. use ROMs, EPROMs, 2 types of 2732s, or a 2764. 3 jumpers and a CPLD do the work of re-arranging the signals.
It appears that I am able to build the board with all new parts, no NOS.. since the Z80 CPU and CTC are still available.
The original MPU shared logic driver chips to route to many different outputs, like lamps, displays, and switches. This design separates the output drivers. IE, if the chip for the displays fails, it will not take out the other outputs. All key chips are socketted.
The switch inputs are read much like a WPC with comparators.
There is surface mount technology on the board for misc parts and discretes, but only because it is less expensive to build that way.
I will press on to get it tested and on the market, please see www.pinballreplacementparts.com.