Help me with microcontroller's keypad interface

[saurav_sdpl]

I am using a 3x4 keypad, instead of giving 7 signals to keypad from micro i want to give just 4 line from micro.
plz help me with the hardware

urgent

 

[IanP]

Re: keypad interface

3x4 keypads have to be connected to 7 lines ..
With 4 lines you can be connected to 2 columns and 2 rows and that means 4 switches ..
If your microcontroller has Analog-to-Digital converter, say, 8-bit you can use it for scanning a keypad of theoretically up to 256 keys ..
In this article you will find more details on how to do it:
**broken link removed**

Regards,
IanP