I revisited an old, abandoned project on KiCAD 4.0.7. While doing the ERC, I saw a peculiar problem. Some of the pins/nets were passing it whereas others were reporting a ‘Conflict problem between pins’. (Pls. see attached pic)
For instance, pin nos. 70 and 71 connected to labels LED5 and LED6 are passing the ERC test but pin no. 72 connected to LED7 is getting flagged. There are several other such errors in the schematic. I zoomed in to check if they are properly connected and they were. Just for your info. Almost every module/sub module of the schematic is having this problem !
What could be the reason? Pls. advise on a remedy.
To me seems like ERC is complaining about pins connected to other pins which are left (unspecified) instead of having proper function (Input, output, power in, power out, passive etc.).
Thanks for your reply. But I am unable to understand your point. Yes, there are several connection where two or three pins are involved. But in the LED case, the pins are simply connected to anodes of individual LEDs. Since I could not draw the LEDs near to the pins of the IC, I placed the LEDs away and simply labeled the wires connected the anode of the LEDs and the IC pins with the same name. In few cases it is OK, in other cases it is not. That is the problem.
The arrow points to one pin that is on the net with the problem. It does not necessarily point to the source of the problem!
In your case the source of all visible ERC errors are unspecified pins. My guess either the creator of the symbol has no clue how KiCads ERC system works or it was done deliberately to force the user to make an application specific symbol. See Electrical type of schematic symbol pins (KiCad 4 and KiCad 5) section “Unspecified” vs. bidirectional for configurable pins.
OK. Thanks for your response, Rene. So what is the solution? This is a 100 pin CPLD IC. I downloaded the schematic symbol from a 3rd party website some time back. There are only few types of pins here - power supply input pins, gnd pins, configurable I/O (bidirectional), clock (most probably input pins in KiCAD) and JTAG programming pins (they are either input, output, bidirectional or clock input pins).
Convert all currently “unspecified” pins into “bidirectional” (or passive) to get ERC to just shut-up and store that symbol in your personal global library
Assign the pin type that best fits your application to every pin and store that symbol in a project local lib
Implementing 2 and 3 should be reasonably fast with the use of the pin table of the symbol editor.
