IC Controls Multiplexed Keypad

Providing a convenient, reliable means of connecting a multiplexed keypad to a µC, the EDE1144 Keypad Encoder IC is designed to interface a matrix-type 4-row x 4-column (16-key or less) keypad to a µC or other host processor. Especially useful in embedded systems, a one-wire serial or four-wire parallel interface returns the keypress data and can be used in conjunction with a data valid signal for polled or interrupt-driven applications. The EDE1144 provides enhanced keypad features such as contact debouncing and key auto-repeat in an easy-to-use package that can lower software overhead in the host µC and reduce I/O pin counts from eight to one. This IC reduces noise by monitoring the keypad with unchanging signals and then scanning only once each time a keypress is detected, rather than continually scanning the keypad.