This invention relates to the field of CAN communication technology, providing a CAN communication circuit and a CAN communication
system. In this communication circuit, the CANH terminal of the CAN
transceiver is connected to one end of a first
resistor and the first port of an
external circuit interface; the other end of the first
resistor is connected to one end of a first
capacitor and the third port of the
external circuit interface; the other end of the first
capacitor is grounded. The CANL terminal of the CAN
transceiver is connected to one end of a second
resistor and the second port of the
external circuit interface; the other end of the second resistor is connected to one end of a second
capacitor and the fourth port of the external circuit interface; the other end of the second capacitor is grounded. When the CANH and CANL terminals of the CAN
transceiver are connected to terminating resistors, the third and fourth ports are short-circuited. This invention achieves the connection of the CAN communication circuit to a terminating resistor without changing the
hardware structure of the CAN communication circuit, unifying the hardware circuit of the CAN communication circuit and reducing the complexity of hardware management.