CAN Protocol Interview Questions. The Top asked CAN interview questions. The CAN Protocol interview questions are the questions in all the automotive companies all over the world. If you are an automotive engineer or any other engineer in Automotive domain, you should know the details of CAN. Going to an interview without CAN knowledge is like going to your marriage without your dress. So, lets check the article.
CAN Protocol Interview Questions
What does CAN in CAN protocol Stand for
Can in CAN Protocol stands for Controller Area Network.
What is CAN Protocol
The CAN protocol is a set of rules that lets the controllers of an Automotive Network Exchange the data at higher baud rates considering the priorities of the the data. The Different CAR ECU’s, including Airbag, Engine, BCM, IPC etc exchange information with each other using CAN.
What are the benefits of CAN Protocol
- CAN protocol works as a multi master protocol so every node on the nework can control transmission of data.
- It has good baud rates.
- With CAN Protocol it is possible to prioritise the data using message Arbitration.
- CAN operates on low voltage levels and so is easy to implement in Automotive networks.
- It is more reliable with lowest data losses.
- It is cost effective.
- CAN protocol is stable and There is no effect on CAN network even if a CAN node gets faulty.
- Has better error handling mechanisms.
CAN Baud Rate Values
The CAN Baud Rate on network can be –
- 125 Kbps
- 500 Kbps
- 250 Kbps
- 1000 Kbps (1000 Mbps is the maximum CAN protocol Baud rate)
Can you Use CAN Protocol to transfer Media
No, CAN does not support sufficient Baud rate which makes it incapable in media streaming on Centre Stack (Multimedia Head Unit) in Cars.
Disadvantages of CAN protocol
- Not possible to stream media using CAN. This is the reason MOST is used as a replacement of CAN.
- Robert Bosch uses the royalty of CAN Patent. So, it is not cheap exactly.
- It requires strong domain Skills to create CAN drivers and architecture.
Voltage Levels in CAN Protocol
CAN bus operates at two voltage levels. The CAN bus electrical specifications with CAN level voltage measurements is –
- CANH voltage level is 3.3 Volt (CAN High at 3 V)
- CANL Voltage Level is 1.8 Volt (CAN Low at 1.8 V)
What is a CAN Line
CAN Line is the actual network channel that has two battery levels which are used to transmit digital data in an organised manner majorly in Automotive networks.
What is CAN Bus
CAN Bus is a group of wires which have different voltage levels to transmit digital data in an organised manner.
What is the difference between CAN Line and CAN Bus
There is no difference between CAN Line and CAN bus.
What is the CAN Network Topology
CAN Network can use any the following Network topology arrangements –
- Star Topology
- Loop Topology
- Bus Topology
What is the Basic Principle of CAN Protocol
CAN protocol is based on Wired AND logic. Wired AND logic means – 0 is dominant. Meaning of Zero dominant is that whenever there is a conflict in two data transmissions,then the sender who is sending 0 will get the priority.
What is Message Arbitration in CAN protocol
Message Arbitration in CAN protocol is a way to distinguish the data frame as per the priorities. The CAN nodes are flexible to transmit any information any time. The Bus supports the wired AND logic, so the sender sending the 0 first will get the priority over the sender transmitting the 1. The bus will show the 0. The network nodes keep on reading the CAN Line data. As soon as they realise that there is conflict in between their sent data and the Bus Data, it stops transmission. Now it happens until a single sender is their. This is the Message Arbitration Process in CAN protocol.
What are the Standard CAN Frame Formats
CAN Protocol has two standard Frame Formats
- Standard CAN Frame Format or the 11 Bit Identifier Format
- Extended CAN Frame Format or the 29 Bit Identifier Format
CAN Protocol Alternatives
The Top CAN protocol Alternatives are
- Flex Ray
CAN Protocol ISO Standard
CAN protocol uses the following ISO Standards
- ISO 11898
- The ISO 11898-1
- ISO 11898-2
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These are the top CAN Protocol interview questions. This is the set of basics. If you are proceeding with the basics, it will be easier for you to understand my complex articles. The interview is always of the thing that interviewer knows and not of what you know. You should never go to any Automotive interview without reading this article. you should Bookmark this now. You can connect with me personally if you have any question related to CAN. Also, I will get you even more details of Automotive technology.