PCF8574AT

The PCF8574AT is a remote 8-bit I/O Expander for I?C-bus with interrupt. It provides general-purpose remote I/O expansion via the Two-Wire bi-directional I?C-bus. The devices consist of eight quasi-bi-directional ports, 100kHz I?C-bus interface, three hardware address inputs and interrupt output operating between 2.5 and 6V. The quasi-bi-directional port can be independently assigned as an input to monitor interrupt status or keypads or as an output to activate indicator devices such as LEDs. System master can read from the input port or write to the output port through a single register.