# Are resistors the only legal way to tie various power designations together?

I'm working with a schematic in Eagle and I use IC's with different types of power pins. I connect VDD to VCC to +5V and I connect GND to VSS to zero volts.

When I look at the ERC, I receive warnings as follows:

WARNING: Sheet 1/1: POWER Pin IC1 VCC connected to VDD
WARNING: Sheet 1/1: POWER Pin IC1 GND connected to VSS
WARNING: Sheet 1/1: POWER Pin IC5 V+ connected to VDD
WARNING: Sheet 1/1: POWER Pin IC5 GND connected to VSS


When I switch over to PCB manufacturing mode, it seems that not all the pins are connected.

My schematic has a microcontroller, CMOS IC's and a 555 timer.

Do I need to add resistors between each of the different power supply designations? I'm trying to be legal so that no electrical software complains.

• I think by "legal" you mean you're trying to eliminate all design rule check warnings. No regulatory body will worry about this. – jbarlow Jul 15 '16 at 6:25
• Try renaming VDD rail to VCC and VSS to GND. Though such behaviour looks strange - you should be able to name your netnames the way you want to – Artūras Jonkus Jul 15 '16 at 6:28
• Warnings are just that, warnings, not errors. – Passerby Jul 15 '16 at 6:28
• related (possibly): How to attach a pin not shown on schematic symbol? – Nick Alexeev Jul 15 '16 at 6:38
• – Peter Smith Jul 15 '16 at 10:41

• VCC and VCC have no special meaning in Eagle. If net contains a pin of direction supply (like the little arrow or ground symbols have), it becomes a supply net. The only reason these warnings appear is that the symbol itself has pins that have a direction of power which is then connected to a supply net with a different name. You could give a pin named bob the direction of power if you wanted and it would then give warnings that bob is connected to supply net (hope it's not mains, otherwise poor Bob). If the supply net has the same name as the power pin, no warning is generated. – Tom Carpenter Aug 3 '16 at 21:52