3 ms·
Yes, certainly! And I admire the author to have put the idea into production. For even more inspiration, the "Application Handbook" linked to on the Wikipedia-
by cnvogel 13y ago
Yes, certainly! And I admire the author to have put the idea into production.
For even more inspiration, the "Application Handbook" linked to on the Wikipedia-page for the MC145000B has a lot more examples similar in spirit: http://en.wikipedia.org/wiki/Motorola_MC14500B http://en.wikipedia.org/wiki/Motorola_MC14500B
But then, in an industrial job, you'd be scolded for the implementation, because only few of the colleagues would be able to follow this thought or make modifications to the logic stored in the 2kByte ROM.
I don't know about the precise time the article-author had put his logic into use, but PALs (the predecessors of FPGAs) were available since 1980 or so, and they should have been sufficient to implement the "printing-press" logic mentioned, and they meet the "programmable" requirement.
http://en.wikipedia.org/wiki/Programmable_Array_Logic http://en.wikipedia.org/wiki/Programmable_Array_Logic
(it seems the 2716 used in the article's schematic was introduced 1977 http://en.wikipedia.org/wiki/EPROM http://en.wikipedia.org/wiki/EPROM )
- dfox 13y agoAssuming that specification of logic performed was in form of some state diagram or flowchart, transforming that into contents of that ROM is pretty straightforward, you just assign memory addresses to states and then follow arrows. PAL seems to be natural choice for this, but: * this circuit has more state than what would fit into PAL22V10 (I don't know if it is really necessary), which is largest common PAL device (it would not fit even into 26V12, might into GAL6001) * rewriting some state machine description into logic equations for PAL compiler is significantly more work than creating contents of that ROM. * PAL programmer is more specialized piece of hardware than (E)PROM programmer.
- noonespecial 13y ago>But then, in an industrial job, you'd be scolded for the implementation... I wish this were true. I work on a Goss/Rockwell that has 40 years of this kind of "cleverness" sprinkled all over it like fairy dust. All I can say is : Please. Don't.