I have a new Smoothieboard and I am attempting to debug a new firmware I'm developing but so far I have been unable to GDB to connect. I am successfully compiling the uploading "make all upload" and then connecting over the USB serial and running commands. But as soon as I run the "break" command or press the ISP button the board just hangs and then after about 20 seconds USB disconnects from my computer. "make debug" runs but just hangs trying to connect to the target and then errors out once the USB port is closed.
I've tried on both OSX and Ubuntu with similar result.
Does anyone have any additional tips for debugging debugging?