We strongly recommend you to connect GND line when you use CAN.
CAN is a differential transmission signal. Therefore it may work without connecting GND line.
But under this condition, there is a possibility that it causes some malfunctions in NETIMPRESS air and your target board (mainly, IC of CAN Transceiver).
CAN is a differential transmission signal. Therefore it may work without connecting GND line.
But under this condition, there is a possibility that it causes some malfunctions in NETIMPRESS air and your target board (mainly, IC of CAN Transceiver).