A simple port expander always comes in handy.
Expand 2 click carries a 16-bit I/O expander. Specifically, MCP23017. It's similar to our other Port expander click in almost every respect, except that it uses an I2C interface instead of SPI. The I2C clock speeds are 100 kHz, 400 kHz, or 1.7 MHz for higher throughput applications.
Like the original Expand click, this one can also use either a 3.3V or 5V power supply, depending on the position of the PWR SEL jumper.
Three addition jumpers (ADDR SEL) are for configuring the board address, which allows for connecting up to eight devices on the bus.