Sunday, February 20, 2011
555 timer could reduce number of pins in keypad interfacing
A 4x3 matrix keypad requires 7 I/O pins of microcontroller for interfacing. But you could reduce the required number of connections to two by using a 555 timer IC. If you want to know how, visit Embedded Lab's new post "2-Wire Keypad Interfacing using 555 Timer".