Communication between two controllers with the different electric grounds for Fail-Operational

As many automotive companies adopt autonomous driving systems, safety is more important than ever. In particular, in autonomous driving levels 4 and 5, design considering Fail-Operational has become an essential element. For Fail-Operational design, it is essential to design two controllers with different electric grounds in one system, and in this case, both controllers must transmit and receive as much data as possible along with periodic continuous communication. A suitable means of communication to implement this would be SPI (Serial Peripheral Interface) with an isolator. During communication between two controllers with SPI, not only data exchange but also system control must be performed, so it is necessary to find and set an optimal transmission speed and a method to reduce CPU load by optimally processing communication data. Therefore, in this paper, try to find the optimal communication data processing method and transmission speed for Fail-Operational of motor control, and to discover unexpected cases that may occur during communication.