The PCF8574 is used to expand one I2C bus to 8 I2C buses. You may use it with your microcontroller to add more digital I/O. It works as I2C expansion hub.
This module becomes a life saver When you run out of pins on your Arduino or any other MCU. This GPIO (General Purpose Input Output) pin extender provides an additional 8 pins (P0 ~ P7) which can be used to output a signal or ‘read a signal as an input.
8 bi-directional data lines
Loop-thru feature allows expansion of up to 8 modules / 64 data lines
I2C interface with jumper adjustable addresses
Interrupt output capability
3.3V and 5V compatible