PCA9537 4-bit I2C-bus And SMBus Low Power I/O Port With Interrupt And Reset

The PCA9537 is a 10-pin CMOS device that provide 4 bits of General Purpose parallel Input/Output (GPIO) expansion with interrupt and reset for I2C SMBus applications and was developed to enhance the Philips family of I2C 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 PCA9537 consists of a 4-bit Configuration Register (Input or Output selection); 4-bit Input Register 4-bit Output Register and a 4-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 or Output Register The polarity of the input port Register CAN be inverted with the Polarity Inversion Register All Registers CAN be read by the system master. The PCA9537 open-drain interrupt output is activated when any input state differs from its corresponding input port Register state and is used to indicate to the system master that an input state has changed. The power-on reset sets the Registers to their default values and initializes the device state machine. The RESET pin causes the same reset/initialization to occur without depowering the device. The I2C address is fixed and allows only one device on the same I2C SMBus
By NXP Semiconductors