The RESET input can be asserted to initialize the system while keeping the V_CCP at its operating level. A reset can be accomplished by holding the RESET pin low for a minimum of t_W. The TCA6424A registers and I²C/SMBus state machine are changed to their default state once RESET is low (0). When RESET is high (1), the I/O levels at the P port can be changed externally or through the controller. This input requires a pullup resistor to V_CCI, if no active connection is used.