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Re: gEDA-user: Linear voltregs: Symbol bugs or features?
Stuart Brorson wrote:
Stuart Brorson wrote:
I am one of the folks who thinks that component symbols should not
have hidden pin connections. Indeed, this problem is really acute
when the symbols live in a library, since newbies won't know that the
pin is connected to GND unless they open up the symbol and look at the
attributes.
As long as you do standard stuff, for example a uC circuit w/
+5V and GND only, everything is fine.
Heh. You've illustrated my point very well. +5V logic supplies
havn't been "standard" for a number of years. Logic supply
voltages are all over the place now. +3.3V is arguably more common
than +5V logic (for commercial-grade designs), and +2.5, 1.8V, and
1.5V are also seen. Therefore, I don't favor "out of the box" symbols
to have hidden +5V supplies.
Exactly. The BIG problem is: What is VCC? Some people say:
VCC is _always_ 5V. Other people say VCC is 3.3V, because
they work w/ 3.3V circuits all the time. Assume one person
from the 5V fraction wants to use the XC9572XL CPLD (or
another 3.3V power supply IC). But the symbol was created
by a developer who only does 3.3V. If nobody pays attention
the result will be blue smoke. So here (and in many other
cases) visible power pins would be really cool.
Maybe one could add a option for each symbol when inserted
in a schematic that the power pins are hidden by default
and made visible if the user wants so (set this magic symbol
to 'yes' or so). Hidden VCC pins could be connected to VCC
by default, but visible VCC pins (one should better call em
+5V or +3.3V or +1.8V and so on) have to be connected manually
to the correct power grid.
Of course there must be a fall-back method for handling old
symbols that aren't upgraded. Sounds complicated. Maybe it's a
really silly idea but who knows.
BTW: It 0:30am local time, so I go to bed now :) No more silly
ideas for about 8 hours.
- cl