The PCF8574N is a 8-bit input/output (I/O) Expander for the two-line bidirectional bus (I2C) is designed for 2.5 to 6V VCC operation. This device provides general-purpose remote I/O expansion for most microcontroller families by way of the I2C interface (serial clock (SCL), serial data (SDA)). The device features an 8-bit quasi-bidirectional I/O port (P0-P7), including latched outputs with high-current drive capability for directly driving LEDs. Each quasi-bidirectional I/O can be used as an input or output without the use of a data-direction control signal. At power on, the I/Os are high. In this mode, only a current source to VCC is active.