EDE1144

The EDE1144 Keypad Encoder IC is designed to interface a matrix-type 4 row x 4 column (16 key or less) keypad to a microcontroller or other
host processor.  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 will lower software overhead in the host microcontroller and reduce the I/O pin
requirements from eight to one, frequently resulting in the use of a less costly host microcontroller in your design.

In addition, the EDE1144 is electrically quiet.  Many keypad encoders continually scan the keypad, radiating EMI noise from the wires leading
to the keypad (resulting in trouble during emissions testing & final product certification & approval).  The EDE1144 reduces this problem by
monitoring the keypad with unchanging signals, and then scanning only once each time a keypress is detected.