When we talk with our friends, we share our emotions and thoughts by using certain language. If someone is talking and others can understand, then we will say it is communication; otherwise, it is just noise. Similar ways exist in electronics. Also, if two or more devices are talking to each other, I mean sending or receiving data on any medium, mostly cables or PCB tracks. Everyone should understand that data, right? That's why some rules are imposed on electric signals produced by devices over the Bus so that every device/node on the bus can understand the significance of the change in signals. These rules can take the form of fixation of bit positions, frequency of the signal, amplitude of signals, etc. In digital electronics, amplitudes stay the same as part of the same rules set. If these signals are packed with meaningful bit positions, that is, if a particular number of bits has a particular meaning, then this becomes frame format. hope you understand... Let's move ah...
Controller Area Network (CAN) protocol is a robust, high-speed communication standard designed to provide fast and easy data exchange between electronic control units (ECUs) in embedded or electronics systems. CAN is originally developed by Bosch in the 1980s for automotive applications, CAN has since become a edge of modern industrial, automotive domain.
WHAT makes CAN unique ?
Usually earlier communication protocols like MODBUS, RS232 etc. are rely on a master-slave system, but CAN works in multi-master and broadcasting message-based communication system. This approach allows multiple devices (ECU's) to communicate with each other being on the same network without any need of a central controller or Master device. CAN has ability to prioritize messages ensures that critical data is transmitted with minimal delay, making it ideal for real-time systems.
CAN protocol characteristics :
1. LOW COST :
This protocol uses simple coper cables which is usually available in low cost. one more thing needed for CAN which is additional to our regular ECU that is CAN transceiver IC, which is also not much costly. have a look of CAN transceiver module .
2. FAULT DETECTION :
CAN has build in error detection capability like Cyclic redundancy code which is also known as CRC.
3. BROADCASTING :
Each device on CAN network can send its CAN frame at any time , every other device will receives that data , and those devices decided which msg frame to accept or not to accept , which is completely depend on how filers are configured in that device. here you may have a doubt what if every device trying to send data over a can at same time , you will get your answer in further series of this posts.
4. PRIORITY BASED COMMUNICATION :
CAN works on priority based message transmission, that means when multiple nodes or device are trying to send their messages on network at same time, those message who has high priority gets transmitted. now again new question in your mind, what about others message?? don't worry we will see it in further discussions. till now remember two points 1st high priority message takes control of network and 2nd all nodes can send their messages without corrupting message.
5. FLEXIBILITY :
If some one added new device to this network or removed from this network , no effect on other device. off course at least two devices must be there. we will discuss this topic also in further discussions.
6. IMMUNITY :
CAN network is highly immune or resistant to external noise which can cause loss of data or corruption in CAN frames.
WHY LEARN CAN?
Over the years, CAN protocol is evolved with advanced specifications to satisfy market new and challenging demands.
Learning and understanding the CAN is important for engineers and developers working with embedded systems especially in automotive domain or industrial automation domain. Although CAN is mostly popular into Automotive domain , but its use is not limited to it. Now days CAN is being used in aviation ,medical electronics, industrial automation etc.
In this blog, we will explore the fundamentals of CAN communication and try to deliver its technical aspects, also we will discuss its implementations in real-world scenarios.
Stay tuned to learn how CAN enables devices to speak with each other in digital world !!
Topics:
CH 1 : Introduction to the CAN Communication Protocol
CH 2 : How CAN Works: Physical layer and Connections
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