For OBD access, the priority is the highest; for in-vehicle host computer access, the priority is medium; for car cloud access, the priority is the lowest. Of course, if there are two types of diagnostic source input, it usually needs to be effectively arbitrated by VDC to ensure its normal response with multiple functions. The arbitration principle is: when two diagnostic services have the same priority, follow the principle of first-come-first-served, equality and mutual exclusion. When a high-priority diagnosis accesses a low-priority Priority diagnostic access. When a low-priority diagnosis accesses a high-priority diagnosis, it is necessary to negatively respond to the low-priority diagnosis service and return to the original route.
For the role of the VDC controller in the central gateway, it is necessary to fully consider its signal routing and protocol conversion requirements. Among them, the protocol conversion includes the conversion of ETH data into LIN/CAN data, the conversion between CAN messages, the conversion between ETH messages, the conversion of CAN diagnostic messages into LIN/ETH diagnostic messages, and the conversion of ETH diagnostic messages into LIN/ETH diagnostic messages. message.