TXD is the interface to the MCU’s LIN protocol controller or SCI/UART used to control the state of the LIN output. When TXD is low, the LIN output is dominant (near ground). When TXD is high, the LIN output is recessive (near battery). The TXD input structure is compatible with microcontrollers with 3.3-V and 5-V I/O. TXD has an internal pulldown resistor. This device does not have a TXD dominant time-out protection circuit so that low data rates may be used.