Communication with the CAN interface card occurs via message channels. A message channel consists of one transmit and one receive FIFO. Message channels can be created exclusively or cooperatively. If message channels are created cooperatively for a certain CAN controller, the data of that CAN controller is distributed equally to the various message channels. The receive FIFO of a message channel supports the access methods "event-controlled" and "polling" where a FIFO fill level mark can be defined to trigger an event. In addition, specific message filtering can be carried out for each CAN controller. The CAN messages are read from the receive FIFO with status and time stamp of the time of reception.
In addition to the standard transmit method, intelligent cards (cards with their own microcontroller system) support extended transmit functions such as the transmission of messages with a time delay, which controls the message flow via a transmit inhibit time, or cyclic on-board transmission, by which high bus loads and exact cycle times of messages can be generated. Also available are incrementing functions which can alter the transmit data.
The VCI supports a plug & play notification system by which the insertion and the removal of CAN interfaces are automatically detected and processed. This makes it possible to remove devices while a VCI application is running.