22 I/O P or t P17-P10 Shift Register 16 Bits Interrupt Logic LP Filter Input Filter 23 P o wer -On Reset Read Pulse W rite Pulse TCA9539A-Q1 2 21 1 12 GND 24 V C C 3 RESET SD A SCL A1 A0 INT I 2 C Bus Contr ol P07-P00