two simultaneous key to perform operation in PIC16F877

[ecaits]

Dear Friends,

Right now I am using 4 key to perform the operation like UP, DOWN, OK & EXIT in my project. But Now I want to perform EXIT operation by remaining three keys. How can I prepare the code???

I mean I want to reduce the keypad from 4 keys to 3 keys....

I am using PIC16F877 with hi-tech C compiler..

Thank you,

 

[wp100]

Hi,

A simple way would be to time the OK key, as short press = OK a long press = EXIT

 

[Gorgon]

If you have any form of feedback, you could make a double push. Ok=short push, as wp100 said above. Push and hold get a feedback, blinking a disply or LED, and then release and push again to exit, inside a time limit.

It all depends on what you prefer. The exit fiunction could also be automatic after a time when no keys are pressed.
How do you enter the function if you only have 3 buttons? Is there more than one function to select? And so on.