PCF8574P Remote 8-Bit I/O Expander for I2C Bus

The PCF8574P is an 8-bit input/output (I/O) expander integrated circuit that communicates over a two-wire I²C-bus. Manufactured by companies like NXP Semiconductors and Texas Instruments, it is primarily used to increase the number of available GPIO pins on a microcontroller (such as an Arduino or Raspberry Pi) using only two control lines: Serial Clock (SCL) and Serial Data (SDA).