More often than not the same chip is available in different packages,
quite often with different number of pins and the packages with fewer
pins omit some of the lesser used signals.
Currently, you need to create a different symbol for every package: if
you have a chip that comes in 5 different packages, with a few pin
differences, you need a symbol drawn for ABC1234-SOIC, ABC1234-BGA,
ABC1234-TSOP and so on. It's the same damn chip, just on some packages
some pins are missing.
I wonder if I'm alone with the wish of having just one symbol, with
every possible signal drawn. Then, when it gets placed to the schematic
with a package selected, the not bonded pins grey out and don't allow
wires to be connected to them?
--
Zoltán Kócsi
Bendor Research Pty. Ltd.