PCA9536

    The PCA9536 is 8-pin CMOS devices that provides 4 bits of General Purpose parallel Input/Output (GPIO) expansion for I²C/SMBus applications of PCA9536 and were developed to enhance the Philips family of IC I/O expanders. I/O expanders provides a simple solution when additional I/O is needed for ACPI power switches, sensors, pushbuttons, LEDs, fans, etc.

   The PCA9536 consists of a 4-bit Configuration register (Input or Output selection); 4-bit Input register, 4-bit Output register and an 4-bit Polarity inversion register (Active-HIGH or Active-LOW operation). The system master of PCA9536 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 read register of PCA9536 can be inverted with the Polarity Inversion Register. All registers can be read by the system master.