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Questions relating to designing PCBs
By voxmagna
#153523
Hi, this is only my third Eagle hobby project. I am learning a lot but I just hit the buffers!

When I look at my Eagle libray components I can see that some have pins defined as VSS and sometime as GND. Similar is true with VCC +5V etc. I cannot assume that all library components will use consistent pin naming

Once the devices are placed on the schematic I want all device pins defined as VSS and GND to be regarded as equal but since they have different NET names they cannot be treated the same. I also discovered that when Eagle throws up a NET error on the schematic, it will not even draw the ratsnest, so there is a big pitfall if you ignore the error. I have learned how to do the 'ground pour' and I think I need to get this conflict sorted out, otherwise I will get unpredictable results.

My question is how can I treat VSS and GND pins used on different components the same in my schematic. I do not want to start creating custom library parts to make the pin designations the same, so they will be on the same net. Is there a way of parsing the active USE library for my project to make all the VSS or GND pins the same before I drop components on the schematic? I read about using 'shorts', is this the only solution? Or is there a utility that will show me all the nets in my project and allow me to rename the VCC nets as all GND?

Sorry if I my question sounds clumsy, but I am freaked out trying to get an error free schematic at the moment.

Merry Christmas to all.
By UNTEngineer
#153559
voxmagna wrote:My question is how can I treat VSS and GND pins used on different components the same in my schematic. I do not want to start creating custom library parts to make the pin designations the same, so they will be on the same net. Is there a way of parsing the active USE library for my project to make all the VSS or GND pins the same before I drop components on the schematic? I read about using 'shorts', is this the only solution? Or is there a utility that will show me all the nets in my project and allow me to rename the VCC nets as all GND?
You probably will have to create custom libraries. Assuming you havent used those parts before, you're going to have to verify that those parts work (footprints, schematics and all). So you're probably going to have to find the datasheet, and do some verification/edits yourself to the parts you are going to use. If you know how the circuit works, and you've done all your math for it, and you're sure that footprints all work out, then you really dont need to bother with that circuit verification feature in the schematic view.

Not sure if its such a good idea to use someone elses library, and rename the VCC nets as GND.
By voxmagna
#154126
Thanks that was pretty much where I was heading, although I did have some success parsing a copy of an Eagle library file and replacing VSS with GND. It only works though when the replacement string is the same number of characters - in this case VSS in the file replaced with GND (all occurences), otherwise the file structure becomes damaged. Thanks for helping