PT6552

V1.3

11

July 2010

MULTIPLE KEY PRESSES

Without the insertion of additional diodes, the PT6552 supports key scan for double key presses in general, triple key

presses of keys on the lines for input pins KI1 to KI5, and multiple key pressed of keys on the lines for the output pins KS1

to KS6. However, if multiple key presses in excess of these limits occur, the PT6552 may recognize keys that were not

pressed as having been pressed. Therefore, series diodes must be connected to each key.

½ DUTY – ½ BIAS LCD DRIVE SCHEME