Abstract
KEYWORDS:
Vehicle Bus, CAN Bus, CAN Controllers
ABSTRACT:
The increasing role of electric and electronic components in a modern car has lead to up to 2,5 km cables and 3000 electric contacts. Classical solutions with parallel, point to point, wiring became ineffective and new solutions, based on two-wired bus systems have been developed (CAN from Robert Bosch GmbH, A-BUS from Volkswagen, VAN
from Peugeot and Renault, J1850 from Chrysler, General Motors and Ford).
The paper presents the basic principles of CAN, which is clearly the leading vehicle bus protocol in Europe and covers the Physical Layer and Data Link Layer of the ISO/OSI standard. CAN bus is an efficient and suitable backbone for linking together the automotive control modules, based on a large amount of numeric processors and ICs (for analog or numeric information processing, motors control, human-machine interface etc.) of different types and with different data length. Today a wide range of applications use CAN for distributed networks. CAN 2.0B is used in the powertrain of many midrange and high-end vehicles for communication between engine management, ABS, transmission control, ASR, active suspension and electronic throttle.
One of the strong sides of CAN is the fact that all important IC producers, INTEL, MOTOROLA, SIEMENS (INFINEON), PHILLIPS, ATMEL, HITACHI, MITSUBISHI etc. have developed a wide palette of controlllers for CAN protocol, of 8, 16 or 32 bits. These are, either, complex processors, able to solve control problems involved by mechatronic systems, or, CAN controllers, destined to connect a certain processor to the CAN protocol. A main part of the paper presents some microcontrollers, which include CAN interfaces and handle CAN messages: Basic-CAN devices, which have
only basic functions concerning the filtering and management of CAN messages; Full-CAN devices, which provide the whole hardware for the functions mentioned above. The paper briefly presents some CAN controlllers from:
INFINEON (Siemens): C515C, C505C (8 bit), C166 family (16 bit), TC1765 (32 bit);
Phillips Semiconductors : SJA1000, PCA82C250 (CAN-transceiver);
INTEL: 82527, 87C196CA.
The intensive use of CAN in the automotive industry, together with rapidly decreasing
pricing of CAN components, attracted the attention of other industrial users. Decisions
in favor of CAN have been made not only by manufacturers of trains, agricultural machines and marine engineering equipment, but also by manufacturers of medical equipment, building automation, household appliances, office automation etc.
The paper is based on the author's studies in implementing bus systems in flexible manufacturing, and also on his attempts for using CAN as a backbone for linking the modules of mechatronic systems together.