I am saddened to hear that this project may not be completed. As an alternative, I would really like to see the H200 CPU logic be written in some sort of VHDL so that it could be compiled into an FPGA or run on hardware simulators. I have started looking through the documentation, but must admit that my ability to "read" the diagrams is severely limited - I seem to be too well trained in 70s-80s logic diagrams.
Rob, would you be able to help get the CPU logic defined in either more-modern logic diagrams or translated into a VHDL? I'm envisioning that an FPGA to run the CPU logic, coupled with static RAM and a "service processor" like a Raspberry-Pi (peripheral controls and control panel) could do a reasonable job of bringing an H200 alive.
What documentation are you trying to read? I don't have any source of much of the detailed logic and am just designing my own to meet the H200 functional specification. If it looks like an H200 and quacks like an H200 then ... who cares about anything else?
The purpose of my project was to experience tackling the types of problems that the original designers had using only the types of components that they had available then. Therefore for example it was legitimate for me to use Honeywell flip-flop ICs from the 1960s in place of core memory in the design of my control memory but I couldn't have used later integrated memory ICs that they didn't have. My machine was intended to be one that they
could have built in the 1960s even if it wasn't exactly like the H200 internally but only behaved like one. Any design that I do now will continue to follow that approach even if I decide not to follow through on the physical construction of the logic boards.
Even laying out logic diagrams is a tedious overhead for me and I tend just to transfer my designs straight to PCB layouts with no intervening steps apart from test runs of the more complicated static logic in a spreadsheet containing all possible states. That approach isn't appropriate for evaluating steps through time cells though and I tend to do that mentally.
By the way, this idea of mentally designing a computer intrigues me. If I conceive the design of a circuit in my mind and it seems to work there then in my experience there is a good chance that the real thing will work. Therefore once I have designed all the circuits in my mind then my brain will actually have stored somewhere within it a complete working virtual computer which it can theoretically use for its own purposes unbeknown to me.
That isn't the interesting part of this thought process though. Suppose I were to conceive within my mind a design for a time machine? If that conceptual time machine actually worked what would my brain do with it? Would I even have to conceive the design
before my brain was able to use it, given that it was a time machine potentially capable of influencing the past behaviour of my brain? This might seem like pure speculation if I hadn't been having these problems with events in my future apparently affecting what I have done in the past for several years now ... I even have a website devoted to the subject but, much like my HoneyPi website, it hasn't been updated for years. Maybe I will get back to work on that in place of HoneyPi now. It is after all literally the future ... On this subject, is my avatar picture at all reminiscent of any character in the
Back to The Future films?
Gosh, I'm appallingly off topic now. It's just as well that I don't visit this site more often.