TCA9539RGER

The TCA9539 device supports 100-kHz (I2C Standard mode) and 400-kHz (I2C Fast mode) clock frequencies. [1]

To reset the TCA9539 device to its default state, the power-on reset feature can be used. This requires the device to go through a power cycle where the VCC is lowered below the POR threshold and then ramped back up to VCC [10]. Additionally, a reset can also be accomplished by holding the RESET pin low for a minimum of tW. This action will hold the TCA9539 registers and I2C/SMBus state machine in their default states until the RESET pin is once again high [8].

The TCA9539 device is typically used as an IOExpander for controlling LEDs, enable or reset signals of other devices, and reading the outputs of other devices or buttons. It is connected as a slave to an I2C master and is placed in a remote location from the master, close to the GPIOs that the master must monitor or control. The device has high-current drive capability for directly driving LEDs and low current consumption. It can inform the microcontroller of incoming data on its ports without the need to communicate via the I2C bus. The TCA9539 is similar to the PCA9555 but with differences in internal features such as the removal of the internal I/O pull-up resistor, replacement of A2 with RESET, and a different address range. It also has improved power-on-reset circuitry for various application scenarios. Additionally, the device can be configured with two hardware pins (A0 and A1) to vary the fixed I2C address and allow up to four devices to share the same I2C bus or SMBus. [9, 9, 9, 9, 9, 9, 9]