On May 31, 2010, at 11:30 AM, Mike Bushroe wrote: > 2) I found that several IC have no power. I know that John Doty does > not like to have his schematics cluttered up with surperfluous Vcc and > Gnd connections. No, I (and others) tend to use separate power symbols, like: [1]http://www.gedasymbols.org/user/kai_martin_knaak/symbols/digital/ 74_pwr.sym Thank you Kai-Martin!
And Thank You, John. I had not seen or heard of that one before, and it would go great on the separate power and bypass cap page to link a specific capacitor with a specific IC. Now I wish that I had equivalents for all the others that don't have by[qass caps inherently in their schematic (voltage regulators, MAX232s, etc). > But at the other extreme, I just discovered that > 7404-1.fp has implicit connections to Vcc and Gnd nets in non-printing > attributes, but the identical looking 7404-4.fp does not. I believe you are confusing pcb footprints with gschem symbols. They are very different things. Yes, my bad. i was writing quickly and imprecisely. It was exactly the SYMBOL that I was talking about, not the footprint. > Is there some > way to indicate which symbols are powerless and which have non-printing > power connections built in? From command line: grep net= `locate name-of-symbol.sym` From gschem: 1. Select the symbol. 2. Hierarchy>Down Symbol 3. Edit>Show/Hide Inv Text 4. Look for net= attributes. > This is especially important in quads and > hex parts that have many slots. And is there a way to change the symbol > used without deleting the instance and re-entering all the data by > hand? The .sch file is text, so a global change of of the symbol name does the trick. > I don't gattrib allows changing the actuacl symbol file used, > just a few of the attributes. These problems are why I recommend making project-specific copies of symbols rather than using the library symbols as-is. John Doty Noqsi Aerospace, Ltd. I had also done some gedit work on the file, and created an error I could not find to undo, so I stopped using direct editing on the .sch files. Perhaps on the next project, when I am not as far behind a hard schedule as I am now for the Underwater Robotics Competition. Mike References 1. http://www.gedasymbols.org/user/kai_martin_knaak/symbols/digital/74_pwr.sym
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