PCA9539

PCA9539; PCA9539R 16-bit I2C-bus and SMBus low power I/O port with interrupt and reset Rev. 9 — 8 November 2017 Product data sheet 1. General description The PCA9539; PCA9539R is a 24-pin CMOS device that provides 16 bits of General Purpose parallel Input/Output (GPIO) expansion with interrupt and reset for I2C-bus/SMBus applications and was developed to enhance the NXP Semiconductors family of I2C-bus I/O expanders. I/O expanders provide a simple solution when additional I/O is needed for ACPI power switches, sensors, push buttons, LEDs, fans, etc. The PCA9539; PCA9539R consists of two 8-bit configuration (input or output selection), input, output and polarity inversion (active HIGH or active LOW operation) registers. 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 read register can be inverted with the Polarity inversion register. All registers can be read by the system master. The PCA9539; PCA9539R is identical to the PCA9555 except for the removal of the internal I/O pull-up resistor which greatly reduces power consumption when the I/Os are held LOW, replacement of A2 with RESET and a different address range. The PCA9539; PCA9539R 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 in...