CAN is a serial interface which is mainly used inside a motor vehicle. Strong noise-immunity is realized with its double signal lines. CAN does not have any clock lines, which means it is an asynchronous interface. Only two signal lines configure the whole network.
The voltage difference between the double signals, CAN.H and CAN.L, represents the data. “CAN.H-high and CAN.L-low” is assigned to data “0”, and “CAN.H = CAN.L”, data “1”. Noises will be cancelled because the transferred data is determined by the voltage difference of the pair of complementary signals.
A data transmitter and its receiver in CAN need to synchronize each other without any clock signals. Once a transmitter sends the first “0” as a start bit, the other all receivers synchronize the transition edge of the start bit.
CAN does not have any master-slave relation. Every interface unit is given each priority order (Identifier) to prevent from competition on the signal lines. When more than two units would start to transfer at the same time and they output their Identifiers after their start bits, each unit which receives a higher Identifier than its own immediately stops the data output. This guarantees that the data of the highest priority unit only can be transferred.
Microcontrollers products incorporating a CAN interface are displayed.