The maximum current that can be sourced or sunk by each I/O pin is 25mA.
The PCA9555PWR can be configured as an input or output by writing to the configuration register (register 0x06). A '1' in the configuration register sets the corresponding pin as an input, while a '0' sets it as an output.
The internal pull-up resistors on the I/O pins are used to pull the pins high when they are configured as inputs. This helps to prevent the pins from floating and reduces power consumption.
The PCA9555PWR can be reset by pulling the RESET pin low for at least 1ms. This resets all registers to their default values.
The maximum frequency of the I2C clock signal is 400 kHz.
PCA9555PWR datasheet
by Texas Instruments
