You are correct the circuit does show a more complete picture and can help enormously to get my answers..
Yes i was able to see that the other 6 can be multi function or special function. Was Pin 5 used for aesthetic or space reasons to even out the pins used, doubtful. Could Pin 5 been used specifically for its
special purpose, External Interrupt?
Yes i already had the data sheets as mentioned in OP.
This from the sensors data sheet;
"The sensor can be easily used to produce a series of CMOS or TTL level logic level or pulse train using a single resistor to limit current. The signal level can be read directly by a digital input. This can be used to interrupt (wake up) a micro controller or can be counted to estimate the amount and duration of activity. The sensor is fully passive, requires no signal conditioning, and draws as little as 50 nA of continuous current."
I would like to use the sensor to (wake up) a micro controller.
Did i just see/answer my own question? Had read that over a couple times and the use of interrupt did not click.
Both. Yes i know that the
micro controller needs to be programmed. I need to be sure what the circuit is doing before i can try to explain to someone what i want the
program to do.