CAN Basic Architectures

Abstract

The basic specification of the controller area network (CAN) communication protocol family comparing CAN, time-triggered CAN (TTCAN), and the recently specified CAN with Flexible Data Rate (CAN FD) is given. The CAN protocol was developed by Robert Bosch GmbH in conjunction and fine-tuned to the automotive and industrial control market with Intel Inc. and the support of Wolfhard Lawrenz as the CAN consultant to Intel. The CAN and TTCAN data link layer and physical layer are standardized in International Organization for Standardization (ISO) 11 898 part 1 through part 5 as well as in Society of Automotive Engineers (SAE) J 2284 parts 1 through 3. CAN networking techniques as well as its protocol characteristics such as frame architecture, bit coding and synchronization technique, multimaster feature, high error detection and recovery capabilities, fault tolerance and speed up to 1 Mbit/s are described. In contrast to CAN, the TTCAN protocol specifies a deterministic variation of CAN. These differences are outlined. The basic networking technology, the TTCAN frame architecture and its synchronization technique are described. The CAN family has been recently enhanced by the CAN FD. This protocol provides a payload of more than 8 bytes of data while maintaining all the other features of the CAN protocol. This chapter explains the philosophy, details and application of CAN FD.