Device provides general-purpose remote I/O expansion for many MCU families via I2C interface

Texas Instruments TCA9555 I2C & SMBus I/O expander, available from Mouser, is designed for the two-line bidirectional bus (I2C) and has 1.65V to 5.5V VCC operation. These devices provide general-purpose remote I/O expansion for most microcontroller families via the I2C interface. The device consists of two 8-bit configuration (input or output selection), input port, output port, and polarity inversion (active high or active low operation) registers. At power on, the I/Os are configured as inputs. The system master can enable the I/Os as either inputs or outputs by writing to the I/O configuration bits. The data for each input or output is kept in the corresponding Input or Output register. The polarity of the Input Port register can be inverted with the Polarity Inversion register.