Overview

Product details

    Provides universal remote I/O expansion via a two-wire bidirectional I²C bus (Serial Clock (SCL), Serial Data (SDA)). The device consists of eight quasi-bidirectional ports, 100 kHz I²C bus interfaces, three hardware address inputs, and interrupt outputs operating between 2.5 V and 6 V. Quasi-bidirectional ports can be assigned independently as inputs for monitoring interrupt states or keyboards, or as outputs for activation indicating devices such as leds. The system host can read from the input port or write to the output port via a single register. The low current consumption of 2.5μA (typically static) is important for mobile applications, and the latched output port drives the LED directly. Three hardware address pins allow eight of each device to be on the same I²C bus, so there can be up to 16 I/O extenders 8574A/PT on the same I2C bus, supporting up to 128 I/ OS (for example, 128 leds). The active low level openbreak interrupt output (INT) can be connected to the interrupt logic of the microcontroller and activated when any input state is different from its corresponding input port register state. It is used to indicate to the microcontroller that the input state has changed without requiring the microcontroller to continuously poll the input register through the I²C bus.