Hello,
I am using three PCF8574 IO expander as slaves and PIC18F4620 as Master. In My application, I have to switch ON relays connected at 8 port pins in a IO expander So, in My case, I am going to use all port pins in IO expander as output (write mode only). For that, Should I send any command bytes to configure port pin direction? and What data should I send to switch on relays connected after master addressing slave. I didn't get that configuration details from datasheet. Below is the schematic that I have used in My application. Please suggest a solution.