Text entry...

Hi everyone,

I'm interfacing a 4x4 keypad with the PIC16F877A to enter text in the same way you do in a cellular phone, but i'm having some trouble regarding the code.

Up till now I've written and tested the code for number entry and it works very well.

Can anyone tell me how text entry can be done (the general algorithm/logic/...) so I can write the code by myself?

thx a lot in advance

regards.

You basically use the keypad as a matrix,

look here:


Couple of links and a couple of different ideas on how to implement, I like the 7 resistor and 1 ADC pin myself.