cell phone keypad programming

[vikrant verma]

hi all,
I want to implement a keyapad same as used in cell phone and in mobile phones.

I interfaced 5x4 keypad with AT89s52 it is working fine, i mapped the key as 0,1,2,3......9 and A,B......H.

now i want it to work like cell phone keypad in which a single key is mapped to different values. like in our mobile phone key number 2 also displays a,b,c
key number 3 displays d,e,f and so on. all it depends on the time inbetween key is pressed.

so if any one is having code of like this please help me.

 

[sri45]

Hi,

As you have done programming keyboard for single press
as checking the keys individually

just make a small change over it
check the key press whether is it the first time or second or third or fourth
if it is for the first time make it to display as a
if it is for the second time make it to display as b

and so on

 

[jayavardhan]

check the key press whether is it the first time or second or third or fourth
if it is for the first time make it to display the first charecter.
if it is for the second time make it to display the second charecter.
for particular time only after that time it should come to the start and when the same key is pressed it should display the first charecter only.

 

[nidhi u]

hi i am also trying to design a cell phone type keyboard with 1 button press means 'a' press it again means 'b' and i got the logic behind it but finding it a little difficult to write the c program for it as this is the first time i am doing something like this. If any one has already written the code for this can you please mail me on nidhi.udani@gmail.com so i can refer to it and build on it.
Thank You.


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