Right on about the FPGAs.   They cost a great deal of money and since they
are not available in "proven through hole technology" making a one off
prototype is even more money.

The goal of the project was to keep the cost way down so other people could
reproduce it and to keep the bus interface the same so that others could get
the feel of retro computing.   The PICs I used were $6 and I was able to
plug them into a solderless breadboard.  The cheapest FPGA solution I've
seen is well over $100 unless you are willing to create a custom PC board
which again is another $75 but you will need a PC board anyway to implement
the other logic.  



jim-142 wrote:
> 
> All,
> 
> I had the same idea a few years back, and I too wrote code to emulate an
> 1802.   I was looking just now for it, but can't find it.
> It was probably on the hard drive that crashed a few months or so ago, and
> couldn't be recovered.
> 
> But my reasoning in response to the question...
> 
> An 8bit PIC I think would be a poorer choice than an FPGA or ARM. Maybe 
> a 32F (MIPS) PIC if you feel you have to support microchip.
> 
> Is...
> 
> You're probably correct in thinking it is a poorer choice than an FPGA or
> ARM.  But in my case, I emulated the 
> the 1802 just because I wanted to see if I could do it.  As I found out, I
> could, and it worked quite well.
> 
> 
> And, my response to the question....
> 
> Why would you do this on other than an FPGA or emulate on a PC if the 
> goal is to design an improved cpu?
> 
> Is....
> 
> Because not everybody that works with, or dabbles with PIC's has the
> knowledge, expertise, experience, hardware, software, etc. to work with
> FPGA's.
> A good number do, but I'd be willing to bet that there are more PIC
> experimenters than there are PIC and FPGA experimenters. 
> 
> Most FPGA's, (Not all), are significantly more expensive than PIC's.  And
> if
> you just want to see if something can be done, a PIC is less expensive
> than
> going the FPGA route.  In addition, learning VHDL and/or VERILOG is a
> steep
> learning curve compared to PIC asm or hll's.  So that would be another
> reason.
> 
> Anyway, that's my take on the subject.    
> 
> Regards, 
> 
> Jim
> 
> 
> 
> 
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