Study On Communication Protocol Of CAN Based On P87C591

The Controller Area Network (CAN) is a serial communications protocol which efficiently supports distributed realtime control with a very high level of security. Its domain of application ranges from high speed networks to low cost multiplex wiring. In CAN specification 2.0A, there are only physical layer and data link layer defined, but actually more functions are required though some simple distributed systems based on CAN are implemented. To design CAN communication protocol can make up for the shortage of CAN specification 2.0A and attain more and better functions.This paper presents a kind of data frame structure applying 8-bit microcomputer 87C591 of PHILIPS. It can transfer data more than 8 bytes based on CAN specification 2.0A and makes up for the shortage of CAN specification 2.0A that can only transfer data less than 8 bytes. At last this paper gives the design of CAN protocol of application layer based on the data structure and attains the convenient and prompt transmission through CAN Bus. At the same time this paper classifies the messages and prescribes distribution of messages' ID according to the system's requirement.At last experimental results indicate CAN protocol of application layer based on P87C591 is very reliable and has good real-time performance. This protocol has been used in the national 863 project.