topic Re: ERC inconsistency in checking unconnected pins in EAGLE Forum

ERC inconsistency in checking unconnected pins

Anonymous — Wed, 17 Apr 2019 10:58:17 GMT

Hi,

There seems to an inconsistency in the way ERC checks for unconnected pins. For example in Projects/examples/tutorial/demo1.sch (refer to screenshot), I disconnected two pins of the header, added a unconnected test point and resistor. ERC reports unconnected pin warning only for X1 and R2, nothing for pin 15 and 16 of the header. All these unconnected pins are passive. Why this is so? Is there a way to list all the unconnected pins in the schematic irrespective of their direction type through ULP or something?

Eagle Version: 9.3.2

OS: Ubuntu 16.04

Screenshot:

Thanks,

Ravikiran

Re: ERC inconsistency in checking unconnected pins

Anonymous — Wed, 17 Jul 2019 06:37:24 GMT

Since this issue still exists in recent version of eagle 9.4.2, I decided to create a ULP to list all the unconnected pins.

ULP shared on GitHub gist:

https://gist.github.com/rkprojects/647b45754eb844d3f4197648c2c7c825

Screenshot:

Re: ERC inconsistency in checking unconnected pins

jorge_garcia — Wed, 17 Jul 2019 21:05:43 GMT

Hello @Anonymous,

I hope you're doing well. Make sure that you are clicking the ERC icon every time and not the yellow triangle icon. The Yellow triangle icon will show you the errors from the last time you ran the ERC check. I've seen a few users make this mistake before.

Let me know if there's anything else I can do for you.

Best Regards,

Re: ERC inconsistency in checking unconnected pins

Anonymous — Thu, 18 Jul 2019 04:34:44 GMT

Hi Jorge,

Thanks for your reply. I run ERC by assigning command to key, I made sure I was clicking ERC icon/using ERC command before reporting this issue.

Regards.

Re: ERC inconsistency in checking unconnected pins

jorge_garcia — Thu, 18 Jul 2019 20:05:25 GMT

Hi @Anonymous,

Thanks for the followup, could you turn on layer 93 Pins and make a screenshot? pas pins don't get any special checks if it's reporting an unconnected pin for the resistor then that may imply that the resistor pins are a different direction, resistors from the rcl library don't report as unconnected even if left with one end floating like in your example. Turning on layer 93 will confirm this.

Direction is important because sometimes you want an unconnected pin and you don't want to flag warnings because of it. It's important to always assign the appropriate direction to your pins in order to leverage the ERC effectively.

Best Regards,

Let me know i

Re: ERC inconsistency in checking unconnected pins

Anonymous — Fri, 19 Jul 2019 10:01:19 GMT

Hi Jorge,

Thanks for your reply, its really nice to see active support. Please refer to the screen shot below with pins layer 93 visible. Resistor R2 pins are pas direction and it is also from rcl library. Now all the unconnected pins are of pas direction but only R2 gets reported. If I try this with any R/C/L/D part I will get same behavior.

I am using Eagle version 9.4.2 (Ubuntu 16.04/Linux ), Project: examples\tutorial\demo1.sch

In general, comparing with other commercial cad tools, unless a unconnected pin is explicitly marked as no connect, it should get reported irrespective of its direction. In a large design we may forget to make a connection or it may be an incomplete connection, if ERC ignores certain directions then these kinds of mistakes will get caught very late in design cycle.

Regards.

Re: ERC inconsistency in checking unconnected pins

jorge_garcia — Fri, 19 Jul 2019 20:44:36 GMT

Hi @Anonymous,

I've pinged our developers on this to see what's going on with the ERC here. I agree with you, I would expect it to show all unconnected pins(with the exception of NC pins since those are obviously meant to be unconnected).

Let me know if there's anything else I can do for you.

Best Regards,