Home Education

 

Classes

Kvaser arranges CAN classes in three different levels, Gold, Silver and Bronze.

  • Bronze - The basic nuts and bolts of CAN
  • Silver - The higher level protocols and real world usage of CAN
  • Gold - Programming Kvaser hardware with CANlib SDK.

For further information, please contact us >>

 

The CAN Protocol

The CAN protocol is defined by the ISO 11898-1 standard and can be summarized like this:

  • The physical layer uses differential transmission on a twisted pair wire.
  • A non-destructive bit-wise arbitration is used to control access to the bus.
  • The messages are small (at most eight data bytes) and are protected by a checksum.
  • There is no explicit address in the messages, instead, each message carries a numeric value which controls its priority on the bus, and may also serve as an identification of the contents of the message.
  • An elaborate error handling scheme that results in retransmitted messages when they are not properly received.
  • There are effective means for isolating faults and removing faulty nodes from the bus.

For further information, view our on-line CAN protocol tutorial >>

 

Higher Layer Protocols

The CAN protocol itself just specifies how small packets of data safely may be transported from point A to point B using a shared communications medium. It (quite naturally) contains nothing on topics such as flow control, transportation of data larger than can fit in a 8-byte message, node addresses, establishment of communication, etc. These topics are covered by a Higher Layer Protocol, HLP . The term HLP is derived from the OSI model and its seven layers.

Higher layer protocols are used in order to

  • standardize startup procedures including bit rate setting
  • distribute addresses among participating nodes or kinds of messages
  • determine the layout of the messages
  • provide routines for error handling on system level

For further information, view our on-line overview of CAN Higher Layer Protocols >>

 

Further information

There are a lot of sources of CAN related information. Here is an attempt to categorize the information in a few different sections.

 

CAN Controllers and tranceivers

At the low level there are, in principle, two kinds of CAN products available on the open market, CAN chips and CAN development tools. At a higher layer another two kinds of products are relevant, CAN modules and CAN design tools. A wide variety of these are now available on the open market.

 

Patents in the CAN Area

Patents relevant for CAN application can be of many different types: synchronization and clock implementations, transmission of large data sets (the CAN protocol uses data frames of just eight bytes length), etc.

Â