The MikroElektronika an Expand 9 Click is a compact add-on board that contains a multi-port I/O expander. This board features the SX1509QB, the world’s lowest voltage level shifting GPIO expander from Semtech Corporation. The SX1509QB comes in a 16-channel configuration and allows easy serial expansion of I/O through a standard I2C serial interface. It also has a built-in level shifting feature making it highly flexible in power supply systems where communication between incompatible I/O voltages is required, an integrated LED driver for enhanced lighting, and a keypad scanning engine to implement keypad applications up to 8x8 matrix.

Low power consumption
Integrated LED driver for enhanced lighting
On-chip keypad scanning engine
Interrupt and reset feature
Selectable I2C slave address