DPRG mailing list archives: [DPRG] Eagle Schematic/Board mess....

Wed May 21 21:38:16 CDT 2008

>> Message: 8
>> Date: Wed, 21 May 2008 16:27:42 -0700 (PDT)
>> From: Ben Clapp <xxx at yahoo.com>
>> Subject: [DPRG] Eagle Schematic/Board mess....
>> To: dprglist at dprg.org
>> 
>> In order to design my first board, I decided to use Eagle... I started 
>> out with the schematic. Everything turned out great, as far I as I could 
>> see... But when I imported the parts for board design, I noticed that 
>> the GNDs and VCC's were connected in all sorts of strange places. For 
>> GND that doesn't matter, but the way VCC is connected right now (in one 
>> giant series, causing too much voltage drain), I can't run anything.. 
>> It's a mess now... Could somebody fix up my Eagle schematic/board files 
>> and teach me how to not completely mess up my circuitry next time? :P 
>> Thanks a ton. Also, if there's anything else strange about my circuit, 
>> please tell me, keeping in mind this is my first design; I don't have as 
>> much experience in electric circuitry as I'd like. :P

> So go ahead and do placement.

Maybe I spoke a little too soon. ;-)

I looked at your schematic... I see a liberal use of "connection dots". You normally don't have to add the dots to connections. The editor will connect a wire to a pin and you won't see a connection dot, but it will be connected. The older versions did you require you to occasionally add a connection dot. I think that was when you created a "T" connection of two wires and they weren't actually connected. 

I also see you have at least one instance where you have a wire connected directly across a resistor. That's usually not a good idea.

So, you can run ERC (It looks like a magnifying glass with a gate in the middle. It is in the lower left corner of the menu.) It will give you a list of errors. Sometimes they are okay, like when it says that you connect nets VDD and +5V. You probably will end up doing that on purpose.

But on you design I see "Net DIGI1 overlaps pin". That means you put dpwn the wire but you missed the pin. So click on the error and it will show you where it is bad. Zoom in and you will see the green line overlapping the brown line of the pin. (Again, you don't need a connection dot here, maybe it added one because you missed the pin.)

Then you have "No pins on netN$4". That is just a wire you placed that is not connected to anything.

So ERC is your friend. Normally you run ERC before you tell it to create a board. So you want to fix the "fixable" errors that show up.

I'll go through and clean up the schematic. And I will note problems that you can watch for.

-- 
Jeff Sampson