On 3/15/2018 10:23 PM, Jeff Laughton wrote: > It's worth remembering, as Jim pointed out in a previous post, that we > haven't gotten the original adapter fully nailed down yet. Also I > apologize for implying, even in jest, that we should coax Jim to up > the ante. That wasn't fair, especially since he's undertaken so much > already. I appreciate the comment. My main concern, though, is the "we found a snippet of success, let's jump miles ahead in the process" mentality of the discussion. 1. The new board isn't here yet, so I cannot test it. 2. As you rightly note, there are still issues to deal with, which will require more testing and maybe even a new board spin. Why CMOS '02s do not work right, but NMOS does, needs to be diagnosed and fixed 3. When I submitted the board for manufacture, I added in some interesting possibilities into the design, which could prove useful. I've not discussed them, as I feel it is premature to do so when the primary goal has yet to be fully achieved, in my opinion. 4. However, in the intervening days, the discussion has already essentially discarded those design possibilities in favor of even more grandiose options. 5. Thus, assuming that I can get the primary function to operate, there is now no incentive to even bother working to implement those initial possibilities. If they are brought to fruition, they will compare poorly with the idea of simply migrating to a more advanced CPU. I'm not stating I find the idea of the '816 to '09 objectionable, just trying to be transparent. I rarely use my B128, so I was not overly concerned with needing a replacement. I undertook the challenge primarily because it was an unknown, it seemed a resource (yourself) had solved the problem on paper, someone on the list expressed a need, and it seemed useful to the community. I'm not sure those same criteria exist for an '816 to '09 adapter. Adapting an '816 to the '09 is actually much simpler. Latch whether opcode is x91 or xb1 when VDA:VPA = 11 & PHI2=1. and then flip mux during the subsequent VDA:VPA=10 & PHI2=1 cycle. No need to perform all of the required logic from the original idea. One can directly use the E pin to select 6509 or '816 bank selection. It almost seems like cheating, as the '816 offers lots of help to the designer. JimReceived on 2018-03-16 07:00:02
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