INTERCONNCETION PROTOCOLS TERM PROJECT

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INTERCONNCETION PROTOCOLSTERM PROJECT

• CAN ANALYZER
• Hüseyin Fatih Lokumcu

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OUTLINE

• Introduction to Controller Area Network
• CAN Analyzer
• Hardware Components
• Software Components
• Software and Hardware Components for the
  demonstration
• Future Improvements

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INTRODUCTION to CAN

• CAN (Controller Area Network) is a serial bus
  system, which was originally developed for
  automotive applications in the early 1980's.
• The CAN protocol was standardized in 1993 as ISO
  11898-1 and comprises the data link layer and the
  physical layer of the seven layer ISO/OSI
  reference.

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INTRODUCTION to CAN

• CAN provides
• a multi-master hierarchy, which allows building
  intelligent and redundant systems. If one network
  node is defect the network is still able to
  operate.
• broadcast communication. A sender of information
  transmits to all devices on the bus. All
  receiving devices read the message and then
  decide if it is relevant to them. This guarantees
  data integrity as all devices in the system use
  the same information.
• sophisticated error detecting mechanisms and
  re-transmission of faulty messages. This also
  guarantees data integrity.

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INTRODUCTION to CAN

• Use CAN if you want to
• Avoid cable pollution
• Immune your system to harsh environments
• Gather time critical data with minimum latency
  (Real time requirements)

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INTRODUCTION to CAN

• CAN Messages
• CAN 2.0A and 2.0B standarts differ only in ID
  size.

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INTRODUCTION to CAN

• CAN Application Fields
• Passenger Cars
• Trucks and buses
• Passenger and cargo trains
• Maritime electronics
• Aircraft and aerospace electronic
• Factory automation
• Building automation
• Medical equipment and devices

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CAN Analyzer

• CAN analyzers are tools for diagnosing CAN
  networks.
• Its job is listening reporting all the activity
  in a CAN bus like message types, frequencies,
  timestamps, etc.

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CAN Analyzer

• Some CAN analyzers avaible on the market
• ADFWEB CAN analyzer tool

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• Lipowsky Industrie-Elektronik CAN analyzer tool
  (CAN Spy)

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CAN ANALYZER

• CAN analyzer developed in this project

CAN microcontroller board
PC
to the bus
CANH
RS232
CANL
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HARDWARE COMPONENTS

• Hardware of the developed CAN Analyzer consists
  of a single PCB with a CAN specific
  microcontroller. (ATMEL T89C51CC02)
• T89C51CC02 is a 8051 based 8 bit microcontroller
  with 512 bytes of ram and 16K flash. It has a 10
  bit adc and a CAN controller with 4 independent
  message objects

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HARDWARE COMPONENTS

• The development board is supplied by ERA
  elektronik, which is a company specialized on
  vehicle electronics.
• It has the microcontroller, power regulator and a
  max232 transreceiver to connect to a PC.

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SOFTWARE COMPONENTS

• Software consists of two parts Microcontroller
  and PC software.
• Microcontroller software is the core part.It
  connects to the bus, listens and reports the
  activity with its uart port.
• Three interrupt driven receiver message objects
  have been implemented so three consecutive can
  messages can be analyzed.

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Activity Diagram of the microcontroller software
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SOFTWARE COMPONENTS

• MICROCONTROLLER SOFTWARE

CAN irq
Main Program
Copy and signal
Receive object1
buffer1
UART
Reenable
Receive object2
buffer2
Receive object3
buffer3
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SOFTWARE COMPONENTS

• Interconnection protocol between the
  microcontroller and PC is a single 19 byte-
  packet containing the data of the received CAN
  message

sync1
sync2
Data 1-7
CAN IDT 1-4
CANCONCH
CANSTMPH
CANSTMPL
sync3
sync4
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SOTFWARE COMPONENTS

• Microcontroller software is implemented in C
  language using keil compiler for atmel products.
  Keil C compiler lets to operate on
  microcontroller register like C variables.
  Microcontroller software is doxygen documentable.

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SOFTWARE COMPONENTS

• PC interface software is developed in Microsoft
  Visual C .NET
• Interface software displays the packets received
  from the COM port which are sent by the
  microcontroller. It also calculates the frequency
  of the messages by using the time id of received
  can packets.

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Software and Hardware Components for the
Demonstration

• For demonstration, a system which transmits three
  different CAN messages is developed.
• CAN2.0A or CAN2.0B messages can be transmitted
• The user chooses frequency(1-100hz) and ID number
  of a message

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Software and Hardware Components for the
Demonstration
PC
CAN Analyzer
RS232
CAN lines
Demo CAN Transmitter
RS232
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Connection Protocols

• The demonstation system consists of three
  devices.(Transmitter,Analyzer,PC)
• All of these devices communicate with each other.
• Transmitter and Analyzer communicates via the CAN
  bus. CAN chips implement the CAN protocol.
• RS232 connections between devices and the PC is
  implemented using a simple protocol

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Connection Protocols

• All of the messages between the PC and devices
  are of this common standard

sync1
sync2
DATA
sync3
sync4

• There are five kinds of messages.
• 1. Transmitter Start Parameters of the
  transmiiter messages.

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Connection Protocols

• 2.Transmitter Acknowledge. (Indicating that the
  transmitter received the parameters)
• 3. Analyzer Start.(Analyzer sends the baudrate
  and standard information of the network to the
  PC)
• 4. PC Acknowledge (PC acknowledges the analyzer.

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Connection Protocols

• 5.Analyzer Received CAN packet (Data and timing
  information of the received CAN packet.
• As you can see,Transmitter and Analyzer devices
  receive only one type of packet from the PC. PC
  receives three different kinds of messages and
  all of these messages have different lengths.
  Thats how, PC differs message kinds and there is
  no length field in the packet format.

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Connection Protocols
CAN Packets
Analyzer Start
PC
CAN Analyzer
PC ACK
CAN Packets
Demo CAN Transmitter
Transmitter Start
Transmitter ACK
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USAGE

• Transmitter is connected to PC. IDs, CAN
  standart(2.0A or 2.0B) and frequencies (1-100hz)
  of the messages are sent to the transmitter.
  Transmittet begins sending messages.
• Then the analyzer is connected to PC. It first
  sends the baudrate and standard of the system to
  the PC and then begins sending received messages.

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Software and Hardware Components for the
Demonstration

• The demo board is the same board as the analyzer
  board
• Software of the demo board is developed in C
  language.
• After the user chooses the parameters via the
  rs232 port, transmission begins and is ready to
  be analyzed.

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Future Improvements

• Since three interrupt driven receive objects are
  used, if four consecutive messages arrive the
  last one will be missed. Instead, four receive
  message objects can be used but it is the max
  number avaible.
• The analyze capability is limited by the
  uart(57600 bps). If suitable system clock is used
  this could be improved to a 115200 for a standard
  PC serial port. Using high baud rate serial ports
  can be considered in order to fully cover 1 mbit
  CANs.

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Future Improvements

• Most of the CAN analyzers on the market use RS232
  ports to report the network. But it may be
  desirable to gather all of the data of network
  and if It is a 1Mbit network, rs232 capacity may
  be not enough. USB or paralel port can be used.
• Some of the devices work independent from the PC
  by recording the data to the local flash. This is
  a very useful case espacially for industrial
  infiltrating.