TI PCA9554ARGTR

I2C to parallel port expander with open-drain circuit and active-low interrupt output, operating power supply voltage range from 2.3 V to 5.5 V, I/O tolerant of 5 V voltage, 400 kHz Fast I2C bus, 3 hardware address pins to support up to 8 devices on the I2C/SMBus, input/output configuration register, polarity inversion register, internal power-on reset, all channels are configured as inputs at power-on, no glitches at power-on, latched outputs with high current drive maximum capability for direct LED driving, latch-up performance exceeding 100 mA, meeting the requirements of JESD 78 Class II specification, ESD protection performance exceeding the requirements of JESD 22 specification, 2000 V Human Body Model (A114 - A), 200 V Machine Model (A115 - A), 1000 V Charged Device Model (C101). This 8-bit expander for the two-wire bidirectional bus (I²C) is designed for operation from 2.3 V to 5.5 V CC. Through the I²C interface [Serial Clock (SCL), Serial Data (SDA)], it provides general-purpose remote I/O expansion for most microcontroller families. The PCA9554A contains an 8-bit configuration (input or output selection), input, output, and polarity inversion (active-high or active-low) register. At power-on, the I/Os are configured as inputs with weak pull-ups to VCC. However, the system master controller can enable the I/Os as inputs or outputs by writing to the I/O configuration bits. The data of each input or output is stored in the corresponding input or output register. The polarity of the input port register can be inverted by means of the polarity inversion register. All registers can be read by the system master. In case of timeout or other improper operations, the system master can reset the PCA9554A by using the power-on reset function to place the registers in their default state and initialize the I2C/SMBus state machine. The PCA9554A open-drain interrupt (INT) 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. INT can be connected to the interrupt input of a microcontroller. By sending an interrupt signal on this line, the remote I/O can inform the microcontroller if there is incoming data on its ports without having to communicate via the I²C bus. Thus, the PCA9554A can remain a simple slave device. The device's outputs (latched) have high-current drive capability for directly driving LEDs and low current consumption. Three hardware pins (A0, A1, and A2) are used to program and vary the fixed I²C address and allow up to eight devices to share the same I²C bus or SMBus. The PCA9554A is pin-to-pin and I²C address compatible with the PCF8574A. However, software changes are required due to the enhancements in the PCA9554A over the PCF8574A. The PCA9554A and PCA9554 are identical except for their fixed I²C address. This allows for up to 16 of these devices (8 of each) on the same I²C/SMBus.