Design and Implementation of Efficient Message Scheduling for Controller Area Network

The Controller Area Network (CAN) is being widely used in real-time control applications such as automobiles, aircraft, and automated factories. In this paper we present the mixed traffic scheduler (MTS) for CAN, which provides higher schedulability than fixed-priority schemes like deadlinemonotonic (DM) while incurring less overhead than dynamic earliest-deadline (ED) scheduling. We also describe how MTS can be implemented on existing CAN network adapters such as Motorola’s TouCAN. In previous work [1, 2] we had shown MTS to be far superior to DM in schedulability performance. In this paper, we present implementation overhead measurements showing that processing needed to support MTS consumes only about 5–6% of CPU time. Considering it’s schedulability advantage, this makes MTS ideal for use in control applications.