What has electrical rules check found?


#1

Electrical Rules Check find these errors in my schematic.


Both VCC pins are set to Power Input, GNDs are set to Passive and the pins with power flags on them are input or output as required. All the trace lines connect properly. What would cause the Rules Failure?


#2

Hi,

The solution is fairly simple:

If you don’t have any power generating symbol in your schematic (any symbol with an power out pin) the DRC will complain that the power nets are not driven.

So for example when you use a connector for your power, the connector is a generic part with passive pins. The DRC can not know, that these pins in your schematics are the power outputs.

For these cases there is a special part in the library called PWR_FLAG. Just attach it anywhere on your +5V (and GND) net.

For an external power Input it might look like this:


#3

I am taking that to mean that I only need to attach the PWR once on each net - 3.3V, 5V, or GND - anywhere on that net. Is that right?

If I may, one other thing. I read somewhere That flags like this image get joined as spider web connections in the PCB. That means I don’t have to run green traces all over the place, KiCad does it for me. Is that right?


#4

Well, if the outputs (pin 2) of the AP1117 are declared electrical type (as it should be), the power flags should be not required.


#5

Yes, correct. In my schematics for power values I prefer to use the power symbols from the KiCAD library instead of global labels (as you can see on my first post).

You’re right. But the parts are part of the KiCAD libraries and the output pin is marked as passive:


#6

You asked the same question back on May 9.


Musical chairs with Electrical Rules Ceck
#7

By the way.
Have you read:
http://docs.kicad-pcb.org/stable/en/getting_started_in_kicad.pdf


#8

That’s why I have my own libs.
Copy a device found somewhere to the editor, correct it and then save it to one of my libs.
Done in a minute - and makes searching for this device next time faster.
Too much faulty things around.


#9

Or, somebody else simply chooses to perform his work, or organize it, in slightly different ways.

Creating and editing both symbols and footprints are not advanced topics for experienced users but rather fundamental tasks you should learn very early in your experience with a layout program.

Dale


#10

We may discuss the problems with managed libraries via email.


#11

I have it on my desktop all the time. I have worked through its training exercise at least three times. I assume you are referring to


As it happens, I don’t find any more information in the ERC report.