PCA9554A

PCA9554; PCA9554A 8-bit I2C-bus and SMBus I/O port with interrupt Rev. 10 — 8 November 2017 Product data sheet 1. General description The PCA9554 and PCA9554A are 16-pin CMOS devices that provide 8 bits of General Purpose parallel Input/Output (GPIO) expansion for I2C-bus/SMBus applications and were developed to enhance the NXP Semiconductors family of I2C-bus I/O expanders. The improvements include higher drive capability, 5 V I/O tolerance, lower supply current, individual I/O configuration, 400 kHz clock frequency, and smaller packaging. I/O expanders provide a simple solution when additional I/O is needed for ACPI power switches, sensors, push buttons, LEDs, fans, and so on. The PCA9554/PCA9554A consist 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. All registers can be read by the system master. Although pin-to-pin and I2C-bus address compatible with the PCF8574 series, software changes are required due to the enhancements and are discussed in Application Note AN469. The PCA9554/PCA9554A open-drain interrupt output is activated w...