Reading the serial port on a DE2 Board

hi,

i have a bleutooth module connected serialy to the DE2 board via the serial UART port on the DE2 board. i have a problem with controling data flow, for example when i send the character "F" i can read this character but i dont know how to read it once and stop reading until i receive the second character i want ro read it once at the right time. could you please help with this problem. to Summarize: when a character is received on DE2 i need to read it once then stop reading until i get the next character.

your help is very much appreciated. thank you