I am doing ERC check and keep getting this error :

only input pins on net ADC7

that net is a pin from an mcu that has a name ADC7 but is not connected to anywhere and shouldn't be connected to anywhere .

So , what does the error means? can i ignore it ?

another warning i get is :

Missing junction in net x

where the net is just some pin that connected to vcc point .

What are junctions needed for? i have a connection, so if i move it i can see its connected, but there is no junction sign(green dot). is that a problem ?

Could you ignore these 2 errors ?

thanks .


2 Answers 2


Missing Junction in Net means that there is a join between more than two wires which does not have a dot on it - the join tool which looks like a cross with a dot in the centre is used to add these. They are actually quite important both visually and to ensure that two nets haven't accidentally become joined when they weren't supposed to be. Imagine you print out the schematic and are following it when trying to build or debug a PCB, you see a cross with no join on it, are the four wires connected? or are they two separate nets? I would assume they are not connected simply because usually in schematics a dot means a junction and no dots means the wires cross over (there is another standard which uses no do to mean junction and a little loop to show one wire hopping over another, but Eagle can't render this, so stick to the dot means junction standard).

Only input on net may or may not be ok. It either means the person that designed the library symbol didn't correctly set the pin directions, or you have only got input pins connected to a net. It's up to you to decide which it is - for MCU pins the direction is usually set to io which will remove this warning. If you have a net that doesn't connect anywhere this is a useful warning to let you know of that, but if it is intentional you can either approve it (with the approve button), delete the net, or add the NC component from the supply1 library to the net to indicate that there are no connections.

  • \$\begingroup\$ Thanks, its an input called ADC of an mcu. I dont want to connect anything to it, so,how can i make this error to disappear?? \$\endgroup\$
    – Curnelious
    Commented Jul 19, 2015 at 13:11
  • 1
    \$\begingroup\$ @Curnelious see my edit - if you add the 'NC' component to the net it indicates that nothing is connected and will get rid of the warning. \$\endgroup\$ Commented Jul 19, 2015 at 13:14
  • \$\begingroup\$ Thanks good answer! But If i remove the net i get "unconnected input".. \$\endgroup\$
    – Curnelious
    Commented Jul 19, 2015 at 13:17

From main menu -> "Place" -> "Directive" -> "Generic No ERC" (Red X)

  • \$\begingroup\$ This answer is extremely terse. Could you explain what you mean? What does this actual do? Which part of the OP's question are you referring to? \$\endgroup\$ Commented May 16, 2018 at 19:56

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