TCA9555 I2C & SMBus I/O Expander

Texas Instruments TCA9555 I²C and SMBus I/O Expander are designed for the two-line bidirectional bus (I²C) and have a 1.65V to 5.5V V_CC operation. These devices provide general-purpose remote I/O expansion for most microcontroller families via the I²C interface. The Texas Instruments TCA9555 consists of two 8-bit configurations (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 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.