Re: digital logic library by 74xxxx part number?
- From: "Peter Alfke" <peter@xxxxxxxxxx>
- Date: 13 Feb 2006 16:02:35 -0800
There is an older generation of designers (my generation) who grew up
thinking in terms of the 7400 data book: 74161, 74138, etc create
instant associations. But we must all realize:
those designs were created between 1968 and 1971, i.e. more than 35
years ago, when designers at Fairchild (I was one of them) and T.I.
defined practical logic blocks that fit into a 16-pin package, and
could be interconnected with a minimum of extra "junk", like inverters.
Those "rules of the games" have changed drastically. 16-pin packages
have become 300- to 1400-pin packages, inverters have evaporated in the
Apparently we did too good a job of indoctrinating the logic designers
to think in terms of MSI functions. But remember, this was created for
your father's or even grandfather's generation. 35 years is an eternity
in this business.
Keep thinking in terms of functionality, draw block diagrams, but leave
the gory details to the synthesizers. R.I.P. 7400 !
Peter Alfke, Xilinx Applications
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