How to connect SMOKE DETECTOR SENSOR with KC868-A64?

[admin]

IIC Bus-1:A

SDA-A:GPIO5
SCL-A:GPIO16

PCF8575:U143 (relay1-16): 100 100 = 0x24
PCF8575:U145 (relay17-32): 100 101 = 0x25
PCF8575:U147 (relay33-48): 100 001 = 0x21
PCF8575:U149 (relay49-64): 100 010 = 0x22

IIC Bus-2:B
SDA-B:GPIO15
SCL-B:GPIO4

PCF8575:U14 (DI1-16): 100 100 = 0x24
PCF8575:U31 (DI17-32): 100 101 = 0x25
PCF8575:U56 (DI33-48): 100 001 = 0x21
PCF8575:U57 (DI49-64): 100 010 = 0x22

do you see clearly? they use two different i2c bus! bus-1 and bus-2 you need to define two i2c bus pin define. if you don't know how to do , you can search by Google, how to define i2c bus in arduino IDE.