While reading microcontroller data sheet i came across i/o types like
ii) schmitt trigger.
I came to know that TTL i/o logic means 0v-0.8v -logic state 0, 2-Vcc means logic state 1 (as per wiki  http://en.wikipedia.org/wiki/Digital_signal#Logic_voltage_levels ).
my questions are
i) what will be the logic state when my input voltage is 1-2 in TTL in i/o type
ii) as per definition schmitt trigger is a circuit with positive feedback, but i didnt understood how it works, advantage of using schmitt trigger type input over TTL