The MAX7323 is a 2-wire serial-interfaced peripheral with eight I/O ports. Four ports are push-pull outputs and the other four are open-drain I/O ports, independent of supply voltage. The four I/O ports configured as inputs are continuously monitored for state changes (transition detection). State changes are indicated by the open-drain INT output. The interrupt is latched, allowing detection of transient changes. When the MAX7323 is subsequently accessed through the serial interface, any pending interrupt is cleared. The four push-pull and four open-drain outputs are rated to sink 20mA and are capable of driving LEDs. The RST input clears the serial interface, terminating any I2C communication to or from the MAX7323. The MAX7323 uses two address inputs with four-level logic to allow 16 I2C slave addresses. The slave address also determines the power-up logic state for the I/O ports, and enables or disables internal 40kΩ pullups for the input ports in groups of two ports. The MAX7323 is one device in a family of pin-compatible port expanders with a choice of input ports, open-drain I/O ports, and push-pull output ports.