At 09:45 PM 6/13/01 -0400, Mike Reagan wrote:
>Wow you mean PADS finally added the capability to place a via without
>stitching in version 3.5 in the year 2000? OH MY WHAT A LEADING EDGE
>PROGRAM, IT DOES VIAS NOW. (joking of course, Brad)
What will they think of next? Pads that are associated so they move
together? Is that why it's called PADS?
[...]
>You are correct, you can configure the DRC fairly well in Protel,
>if they would add a no error directive on PCB that would be cool but could
>be also dangerous, I guess I would rather see a DRC flagged out than not
>at all.
A no error directive on PCB would basically be a design rule that would
suppress, as I conceive of it, a specific error message. If the design
rules were completely flexible, we might not need this, but they aren't and
they won't be.
Such a directive would be no more dangerous than any design rule. You can
fool yourself into thinking a board has no errors by making the design
rules such that an error is ignored. Likewise you could do this with a
No-Error rule. But you have to do it deliberately, and it is documented as
a rule. The advantage is that, once you have truly verified that a
condition is *not* an error, but rather some kind of exception that you
*want*, you could quickly validate it and not have to look at it again. If
the board were changed sufficiently so that the error message changed, the
no-error directive wouldn't work.
> Even the RF designs I do, I can generally have a clean DRC when I
>am ready to finish.
I just thought I'd mention something that hasn't come up for a time:
virtual shorts. Consider a two-pad part with, say rectangular pads with a
gap of 50 mils. Now lengthen the pads so that they *almost* contact each
other. Leave a gap of .004 mils. Define a design rule that allows that part
to have a clearance of .002 mils. Presto! a shorting piece of copper that
DRC will consider isolated. Just what you need for many RF copper
components. (Fills can also be used to accomplish this, and the exact
dimensions to use can be a little tricky because Protel DRC gets a little
dicey below .005 mil.)
[EMAIL PROTECTED]
Abdulrahman Lomax
P.O. Box 690
El Verano, CA 95433
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