DRC is not perfect, so you have to choose the most appropriate function to assign to a pin.
With your 555, I would assign, pins 1 & 8 as power 7 open collector 3 outputs 2, 4, 5,& 6 as inputs Of course you could use the 555 as a simple switcher and thus use it to provide some power, in such cases you either respecify the pin or you leave it as is and if needed add a power flag to the output connection to keep the rest of the circuit happy. You WILL get anomalies like this from time to time. Just wait until you use microprocessors where the pins can be inpiut output, bidir, timers or whatever o a programmable basis! You usually end up creating a specific part for a project. Diodes are usually defined as passive Likewise a battery is usually defined as a passive You might think that defining it as a power out is more logical, and you could do so. However you may be dealing with a rechargeable battery, so you would want to connect power INTO it for charging. If the Battery was defined as a power out then DRC would get upset again. What is causing some confusion is that you know what a device does, and are thinking of it in those terms. What you have to remember is that DRC is not very clever, (it does not need to be) all it needs is just enough to detect something silly, like you connecting two output pins together. or not connecting a power pin up. Something like a transistor would have the base as an input, but collector and emitter as passive simply because you can connect them up in various configurations and it's a bit pointless trying to define things any more than that. I understand what you are saying regarding the component numbering, but it looks as if that function is just not available, but it was thought about in the past. Most of the components you will use have already been defined, so if you are makig up your own libs and modules, you can always have a look at what similar parts have done. (That's what I usually do) It does get easier after you complete a few projects. Like most things there is a learning curve to work through, but I must admit that kicad was easier than some packages I've come across. It's also a lot more accessible, as all the files are simple text based, so it's possible to fix a lot of things externally when they don't quite meet your needs. You will see quite a few references to varioyus scripts that users have produced to cater for various requirements. Andy On Wed, 05 May 2010 23:51:16 +0200 Bernd Wiebus <bernd.wie...@gmx.de> wrote: > Hello Andy. > > > > you may have seen the pin definitions in the eeschma help document it's > > quite extensive. > > Most of them are fairly obvious, and you choose from them as needed. > > Mmmmh. Think of a classical 555. You can enable it with setting Pin 4 > high. Pin 4 is normally a signal input, but very very often it is tied > to the power (personally, i prefere doing this with a 4k7 > resistor).....Pin 7, the output, is normaly a signal output. But it will > turn to "power", if you switch with this output the power of a small, > but entirely complete circuit. > What is an Accumulator? Is it output, input or is it passive like a > capacitor? ;-) > At the beginning, i used "open collector" even for single Transistors, > because i did not notice, that this is only for the open collector > switching stages of some ICs. > I had to use the connections of a diode as passive, but for me, a diode > is not necessarily a passive component. > Perhaps it is only a mental problem for me, to make this decisions, but > it is really a problem. > > > It > > is the pin assignments that DRC uses to The danger of using undefined > > and so on is that drc will then not work very well if at all. However > > for things like connectors, then passive is a reasonable choice. > > Of course, with the drc i find all cases of pins not correctly attached > to a wire..... > > > > > The ratsnest of the wires, that's another matter You can of course > > limit what you see with the show general and module ratsnest options, > > but the main problem is that Kicad will not know which pin the main > > board trace will connect to until you actually connect it. Hence ypou see > > the ratsnet. A small case of chicken and egg I'm afraid. > > I see..... > > > > > As for the sheet name, well the docs do refer to this function, noted as > > not implemented, but the docs are for a rather older version, so it looks > > as if this idea has been thought of, but as far as I can see nothing > > has been done with it. > > Oh. I do not mean, that the pre- or suffix must be only the sheet name. > But it would be nice, if you could see by the component reference > number, to which part of the board i will belong. > As an example, using numbers 0-999 for the main schematic, numbers > 1000-1999 for power supply, 2000-2999 for driver and power stages, > 3000-3999 for safty circuit and so on..... > But i think, it could be easier use the reference number as a string, > and add another string to it, than reserving hole number blocks for the > use by special sheets. > > With best regards: Bernd Wiebus alias dl1eic > > > > > > > > ------------------------------------ > > Please read the Kicad FAQ in the group files section before posting your > question. > Please post your bug reports here. They will be picked up by the creator of > Kicad. > Please visit http://www.kicadlib.org for details of how to contribute your > symbols/modules to the kicad library. > For building Kicad from source and other development questions visit the > kicad-devel group at http://groups.yahoo.com/group/kicad-develYahoo! Groups > Links > > >
