I may have a requirement to send a small amount of configuration data (<= 16 bits) to some small/cheap AVR boards, which have no interface to the outside world except power and ground. It seems feasable to send this configuration data by cycling power to a board in a controlled manner. The AVR could use a combination of EEPROM and time from powerup to receive and decode the data.
I haven't worked out any details yet, this is more a thought experiment at this point. Any comments?