I should chime in here. I have an unused PIG 2 collecting dust because I have no manual (No idea why not). I was never able to contact the original author dkpinball (he has an account on here but it is not used). I do have a copy of the PIG 1 Manual, but it was an analog device that just used on off and invert logic, as well as a couple dimmers.
The PIG 2 used programming to achieve much the same with additional functionality, and with a bit of experimenting with the default code it can probably do the same easily, but I am sure that it could be programmed to do more and effect timings and that sort of thing.
What I can see is that you were able to map each of 4 Inputs (plus a separate GI input) to any one or more of four outputs simultaneously, with a "buffer" which I guess might allow only a certain number of hits on a trigger circuit to be stored and executed? And an inversion setting which be "normally on" and "normally off" settings.
Each of the 4 outputs allows a power setting, fade, delay, a mapping to the GI and a few other settings I don't understand that control repeats delays, decays and resets.
It can also be mapped to servos (there is a 6 pin connector for 2 Servo motors) controlled by each of 6 inputs (although where all 6 inputs come from I am not sure given there are only 4 inputs plus a GI Input.
There is an AUX 4 pin connector as well.
The firmware update adds commands for inverting the output. It is set up to download via USB from a Windows machine using avrdude.exe (and includes a copy and drivers).
Maybe one day I'll have time to plug it in to some test power and switches to see if I can figure out more of its logic.
IF anyone has a copy of the V2 manual, I would greatly appreciate it,
OR if someone WANTS a PIG2 then I would happily sell mine for $50 plus shipping.