Re: gEDA-user: Two things ... or actually, three

[Russell Dill <Russ.Dill@xxxxxxx>]

> To my knowledge this is not the case right now. Of course the pin numbers
> should not be shown on the schematics: they would use up too much schematics
> real estate and are not interesting anyway (even relatively simple and cheap
> FPGA devices like XC3S700A has 88 power pins in the 256 pins BGA package,
> that's ~35% of the pins): you can't check anything in a BGA package and even
> on package that can be probed, it is extremely hard to find, say, a bad solder
> joint since all pins of the same power rail are internally connected together.

I find that in FPGA design having all pins on the schematic is not an
annoyance and is actually a necessity. I usually just make a single
component that has all the pins of one type. Eg, a component that
contains all the ground pins. I can then draw a net across all the
pins connecting them all and then a single ground symbol. The
separated out pins are very important for bank power as individual
banks can be power by different supplies.

For an XC3S700A, a single schematic page showing how power and ground
pins are connected is extremely cheap and provides an easy way to do a
verification against the data sheet, even by a third party review.


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