Introduction - If you have any usage issues, please Google them yourself
4 × 4 matrix keyboard recognition processing, the keyboard handler task is: to determine whether the key press, to determine which one key press, what key features are would also like to eliminate the disconnect button when in the closed or jitter. Population both in parallel, an output scan code, line by line so that the dynamic ground button, and the other parallel port status input keys from the line scan values and the formation of a common feedback signal coding and identification of key buttons, through the software look-up table for identifying the key function.