Hey I am trying to figure out a way to be able to read a signal from a USB, and decipher whether or not that signal is actual data, or just the USB heartbeat signal, which simply means the USB is still on. I am thinking I would need to use a PLD, or FPGA. Any references to websites or personal knowledge would be greatly appreciated.

 

Do you have a copy of the USB specification? If not, do you know where to get one?