PT6554_10 Datasheet, PDF (17/30 Pages) Princeton Technology Corp – LCD Driver IC

PT6554
Note: DO is an open - drain output and requires a pull-high resistor between 1KΩ to 10KΩ.
KEY SCAN OPERATION FOR MULTIPLE KEY PRESSES
For dual key press operation, PT6554 can perform key scan operations without any need for a diode to be connected.
For triple key press on the KI 1 to KI5 lines, multiple key presses on the KS1 to KS6 lines, and other multiple key presses
require a diode to be connected in series with each key. Connecting a diode will ensure that only the keys that were
pressed will be recognized. Applications that cannot determine triple or more multiple key presses must check the key
data for three or more 1 bit and ignore such data.
V1.4
17
June 2010