Used Power instead of Supply on parts

John Bachman schrieb:

I have my schematic all done and have discovered that I should have used

Supply for ground connections to some of the ICS.  ERC comes up with an

error in places where I connected Vss to GND.  Do I need to go back and

correct every part or can I just ignore the ERC warnings?

Pin direction "supply" is for those pins that provide power, like within

the GND and VCC symbols. The name of a net connected to that pin will

implicitly taken from the pin name (if possible).

Pin direction "power" is for those pins that need to be connected to a

power source, like the power supply pins of ICs.

ERC will warn you if you connect different supply pins to one net (which

can only have one name, so that's a conflict). ERC will also warn you if

you don't connect the correctly named net to a power pin of any device.

Besides that, only the net names and their connections are really

relevant. You might as well remove all power supply symbols and just

name your nets correctly (take care of implicit power gates!).

If you use different IC families with the same supplies, ERC will always

report many warnings, since the power pins of the devices are named

differently (i.e. GND, VSS or V-) but are connected to a single net.

You can safely ignore these warnings as long as you know that these

connections are really wanted in your design.

Tilmann

John Bachman schrieb:

I have my schematic all done and have discovered that I should have used

Supply for ground connections to some of the ICS.  ERC comes up with an

error in places where I connected Vss to GND.  Do I need to go back and

correct every part or can I just ignore the ERC warnings?

Pin direction "supply" is for those pins that provide power, like within

the GND and VCC symbols. The name of a net connected to that pin will

implicitly taken from the pin name (if possible).

Pin direction "power" is for those pins that need to be connected to a

power source, like the power supply pins of ICs.

ERC will warn you if you connect different supply pins to one net (which

can only have one name, so that's a conflict). ERC will also warn you if

you don't connect the correctly named net to a power pin of any device.

Besides that, only the net names and their connections are really

relevant. You might as well remove all power supply symbols and just

name your nets correctly (take care of implicit power gates!).

If you use different IC families with the same supplies, ERC will always

report many warnings, since the power pins of the devices are named

differently (i.e. GND, VSS or V-) but are connected to a single net.

You can safely ignore these warnings as long as you know that these

connections are really wanted in your design.

Tilmann