74HCxxx Models for event based digital simulation for KiCad 8.
Uses ngspice U devices, which trigger very fast event based simulation.
Connections are made according to KiCad library symbols, no pin
assignments are required.

A video at https://www.youtube.com/watch?v=TEfvVOEF0e0 explains how
to create such models.

The digital nodes are listed in the "Spice Simulator" window, but
cannot be plotted. If you want to plot a node, add a 1Meg resistor
from the node to ground to translate it to an analog node. Do this only
for the nodes to be plotted.

You also may employ gtkwave with a ngspice .control script and a 
tcl script for gtkwave to plot the digital data directly.
