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Old 08-10-2007, 10:51 PM
herby1620 herby1620 is offline
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Join Date: Aug 2007
Posts: 4
Default The design of the Altair 680

While I agree that the 1702's were in the original, one must consider one thing: They were obsolete when the thing was designed. No fault of yours, only the Altair people.

My original design of my 6800 CPU board (back in 1975) used a 512x8 EPROM (a National Semi 5204 as I remember it) which was more reasonable then. It needed a -12 supply as well, but worked quite well. The next year Intel released the +5 only (on read) 2716 which was real nice. I used it in a later revision of the CPU board so I could include bootstrap programs.

One thing I was able to do was build a 2k-2k board that has a single 2716 and 2k (16 chips) of 2102's. The 2716 part even included the timing to make a programmer (you needed to add the Vpp supply). In that I was able to get Tiny Basic in the rom, and use the ram work working storage.

Those were the days......
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