Noob here. Creating my first design and I’m having a problem with the ERC. Part of the design requires an AND gate so I thought I’d create one using two NANDs from a 74LS38, the second one acting as an inverter by connecting the inputs together. However, when I run the ERC it complains that one of the inputs to the inverter NAND is not driven by any output. Am I doing something stupid or is this a bug?
I’m running KiCad 8.0.4 on Manjaro.
I can repeat this on Win11. If I use 74LS00, it doesn’t happen.
The 'LS38 is an open collector output, so a little different.
I think that this is still a bug.
Is there a pull up resistor on the inverter inputs?
I doubt ERC understands pullup resistors. There should be one with an OC output.
ERC is NOT a circuit simulator and does not understand your design
Are you saying one should design one in (one should), or that an OC output has one (it does not)?
But the resistor terminal will be passive and that may clear the ERC.
Also according to the pin conflict table, the combination of OC and Input should be ok.
We need to see the schematic.
Edit: Putting in a pull up resistor clears the error.
Thanks guys, a pull-up certainly fixes it. It just shows my limited understanding.