ATMega32u4 Sleep Problem


This is my first question on this forum and I am still pretty new to the whole AVR world. I appreciate any help in advance.

I have built a custom PCB with an ATMEGA32u4. For the most part, the project is a success. Right now, I am programming it over an ISP header and want to move to USB once I get other issues resolved.

The big issue I have right now is that I cannot get it to wake up from sleep on a LOW signal to INT0. If I have it look for HIGH, it will wake right after sleep, but I want it to wake only after I hit the INT0 button.

I am powering it off either an external battery or the ISP.

I am wondering if the USB has something to do with it and it is possibly keeping the interrupt from firing when my button (btn1) is pressed. Any ideas are welcome and appreciated. Here is my code.