Bus Voltages and Levels

The LIN bus data signal operates between 0 and VSUP volts, with the absolute maximums of transceivers running between -0.3 and 40 volts. VSUP is specified to be between 7 and 18V and is typically a single power source across the entire bus. The LIN protocol is a dominant-low protocol, and both dominant and recessive levels are defined relative to VSUP. The recessive level is any level higher than 60% of VSUP and dominant is any level lower than 40% of VSUP. As these levels are outside of the normal operation range of the PIC® microcontroller (MCU), LIN communication between the PIC MCU is achieved by connecting to an external transceiver device, such as the ATA6662C, that runs off of VSUP , and interfaces between the LIN bus and the UART RX and TX lines on the PIC MCU.