FPGA Hardware Based Emulation:

I only discovered FPGA technology recently.  It’s pretty cool, but initially baffling stuff.

FPGA stands for Field Programmable Gate Array. PC Magazine’s Online Encyclopedia defines it this way:

A type of gate array that is programmed in the field rather than in a semiconductor fab. Containing up to hundreds of thousands of gates, there are a variety of FPGA architectures on the market.

What the hell does that mean? Well… every processor has its logic operations (all possibilities of available mathematical/digital processes) hardwired in its architecture.  Every single operation, from bit shifting left to multiplying, is available as a circuit to be used by software. These are Logic Gates or ‘gates.’ You can think of these ‘gates’ as neural connections inside the chip that give it both its unique character and its processing capabilities.

A blank disk can be programmed to have any software on it (provided it fits in the space available). Likewise, an FPGA has a bunch of ‘logic gates’ that can be combined and implemented to exactly replicate the operation of any processor (within its limits defined by the number of gate arrays).  What this means is that the Apple II can potentially be replicated EXACTLY using an FPGA method.

Several groups have done this already:

Columbia Professor’s Report on Apple II FPGA

AppleLogic.org FPGA Apple II Stuff

FPGAs allow a user to build a very exacting, small, and efficient Apple II, but require learning a whole new set of skills – CPU Design – Use of Design Tools – Use of New Hardware – etc.  Every tool has its cost, but ultimately the COST of these FPGAs is rather steep.  Paying $350 for an FPGA that will be mainly used for an Apple II is interesting, but not cost efficient.

I have provided this discussion and links primarily for education, or those already familiar with FPGA based solutions looking for Apple II links.


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