That just the full version of the partial one you posted (or at least 'fuller'), you've already pointed out that PC1 is connected to Vcc, which it doesn't show on that PDF, so it might have no bearing on what you actually have.
However, it's rather bizarre having 1K pull downs? (VERY wasteful of current), even more so when they appear to be connected from Vcc to ground. There's a third one on PB4, this time with a switch to Vcc (if the circuit can be believed), again far too low a value for such a use.
I've just noticed what PC1 is doing, it connects to J1, which is a switched socket - and connects PC1 to Vcc, until you plug something in the socket.
There are plenty of free I/O pins, why not use one of those?.