I was trying to understand the working of this circuit, but couldn't figure out, how does it generate a square wave.
Here is what I figured out by looking at this. The Op-Amp behaves as a comparator. Assuming output to be +3V initially, the capacitor will charge. Once it charges the output will be -3V.
The bottom circuit, looks like a divider giving -1.5V at the non-inverting input.
What happens next?