CAN Protocol Implementation for Data Communication

Abstract

The main aim of this project is the implementation of 
CAN protocol for transferring information from one 
place to another place.   
CAN is a multi-master broadcast serial bus standard 
for connecting electronic control units (ECUs). 
Each node is able to send and receive messages, but 
not simultaneously: message(consisting primarily of 
an ID usually chosen to identify messagetype/sender 
and up to eight message bytes) is transmitted serially 
onto the bus, one bit after another this signal pattern 
codes the message (in NRZ) and is sensed by all 
nodes.   
The devices that are connected by a CAN network 
are typically sensors, actuators and control devices. 
A CAN message never reaches these devices 
directly, but instead a host processor and a CAN 
controller are needed between these devices and the 
bus.    
If the bus is free, any node may begin to transmit. If 
two or more nodes begin sending messages at the 
same time, the message with the more dominant ID 
(which has more dominant bits, i.e., bit 0) will 
overwrite other nodes' less dominant IDs, so that 
eventually (after this arbitration on the ID) only the 
dominant message remains and is received by all 
nodes. Bit rates up to 1 Mbit/s are possible at 
network lengths below 40 m. Decreasing the bit rate 
allows longer network distances (e.g. 125 kbit/s at 
500 m).   The programming language used for developing the 
software to the microcontroller is    
Embedded/Assembly. The KEIL cross compiler is 
used to edit, compile and debug this program. Micro

Flash programmer is used for burning the developed 
code on Keil in to the microcontroller Chip. Here in 
our application we are using AT89C51 
microcontroller which is Flash Programmable IC. 
AT represents the Atmel Corporation represents 
CMOS technology is used for designing the IC. This 
IC is one of the versions of 8051