PCA9554AD,112 (NXP)

The PCA9554AD,112 is an 8-bit parallel Input/output (GPIO) Expander for I?C-bus/SMBus applications and were developed to enhance the NXP Semiconductors family of I?C-bus I/O expanders. The improvements include higher drive capability, 5V I/O tolerance, lower supply current, individual I/O configuration, 400kHz clock frequency. The I/O expander provides a simple solution when additional I/O is needed for ACPI power switches, sensors, push buttons, LEDs, fans and so on. It consists of an 8-bit configuration register (input or output selection); 8-bit input port register, 8-bit output port register and an 8-bit polarity inversion register (active HIGH or active LOW operation). 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 port or output port register. The polarity of the read register can be inverted with the polarity inversion register.