JAJSN80E August 2009 – May 2022 TCA9535
The TCA9535 device is a 16-bit I/O expander for the I2C bus and is designed for 1.65-V to 5.5-V VCC operation. It provides general-purpose remote I/O expansion for most microcontroller families via the I2C interface.
The TCA9535 consists of two 8-bit Configuration (input or output selection), Input Port, Output Port, and Polarity Inversion (active-high or active-low operation) registers. At power-on, the I/Os are configured as inputs. The system controller can enable the I/Os as either inputs or outputs by writing to the I/O configuration register 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 controller.
The TCA9535 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 controller 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 TCA9535 can remain a simple target device.
The device outputs (latched) have high-current drive capability for directly driving LEDs. The device has low current consumption.
The TCA9535 device is similar 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. The TCA9535 is equivalent to the PCA9535 with lower voltage support (down to VCC = 1.65 V), and also improved power-on-reset circuitry for different application scenarios.
Three hardware pins (A0, A1 and A2) are used to program and vary the fixed I2C address and allow up to 8 devices to share the same I2C bus or SMBus.