canChannel

Connection to CAN channel through specified device

Since R2021b

Description

Use this object to create a connection to the CAN channel through the specified device connected to the Raspberry Pi^® hardware. To transmit and receive data from Raspberry Pi hardware through the CAN bus, use the Object Functions.

Note

To generate C/C++ code for this object and its associated functions, you must have an Embedded Coder^® license.

Creation

Syntax

ch = canChannel(raspiObj)

ch = canChannel(raspiObj,device)

ch = canChannel(raspiObj,device,Name=Value)

ch = canChannel(raspiObj,interface)

ch = canChannel(raspiObj,interface,Name,Value)

Description

ch = canChannel(raspiObj) creates a CAN channel.

ch = canChannel(raspiObj,device) creates a CAN channel through specified device.

ch = canChannel(raspiObj,device,Name=Value) also specifies the channelName or sets the BusSpeed and SilentMode properties using one or more optional name-value arguments.

ch = canChannel(raspiObj,interface) creates a CAN channel and sets the interface property.

ch = canChannel(raspiObj,interface,Name,Value) also specifies the channelName or sets the BusSpeed and SilentMode properties using one or more optional name-value arguments.

Input Arguments

raspiObj — Connection to Raspberry Pi hardware board

object

Connection to a Raspberry Pi hardware board, specified as a raspi object.

Data Types: object

device — CAN Device

PiCAN2 | PiCAN2 Duo | PiCAN3

The CAN shield device.

Example: PiCAN2

Data Types: string

Name-Value Arguments

Specify comma-separated pair of Name,Value arguments. Name is the argument name and Value is the corresponding value. Name must appear inside quotes. You can specify several name and value pair arguments in any order as Name1,Value1,...,NameN,ValueN

Example: ch = canChannel(raspiObj,"PiCAN2", "BusSpeed", 500e3)

channelName — CAN channel for transmission

CAN A (default) | CAN B

CAN channel for transmission, specified as CAN A or CAN B. You can use this input argument along with BusSpeed and SilentMode properties for the PiCAN2 Duo board.

Properties

interface — CAN Interface

can0 | can1

CAN interface, specified as can0 or can1.

Example: can0

Data Types: string

ProtocolMode — Communication protocol

Read-only: CAN (default)

This property is read-only.

Communication protocol, returned as CAN. This property specifies the protocol used for communication.

>> ch.ProtocolMode

ans =
    "CAN"

Data Types: string

BusSpeed — CAN bus frequency

500000 Hz (default) | 1000000 Hz | 250000 Hz | 200000 Hz | 125000 Hz | 100000 Hz | 62500 Hz | 50000 Hz | 40000 Hz | 31250 Hz | 25000 Hz | 20000 Hz | 12500 Hz | 10000 Hz | 8000 Hz | 5000 Hz

CAN bus frequency, specified as a number.

SilentMode — Option to set CAN channel in silent mode

false or 0 (default) | true or 1

Option to set CAN channel in the silent mode, specified as a numeric or logical 1 (true) or 0 (false). If you set SilentMode to true, the CAN channel only receives messages and does not transmit.

Database — CAN database information

ch.Database | []

CAN database information, specified as a can.Database object or as an empty structure [ ].

To set this property, you require a Vehicle Network Toolbox™ license.

db = canDatabase(exp.dbc);
ch.Database = db;   
    

Object Functions

Use these object functions to transmit and receive messages from the CAN bus.

read	Read messages from CAN channel
write	Write messages to CAN channel

Examples

Create canChannel Object for PiCAN2 Shield

1. Create a Raspberry Pi object.

   raspiObj = raspi("192.168.1.101","pi","raspberry")

   raspiObj = 
   
     raspi with properties:
   
            DeviceAddress: '192.168.1.101'                
                     Port: 18734                         
                BoardName: 'Raspberry Pi 3 Model B+'     
            AvailableLEDs: {'led0'}                      
     AvailableDigitalPins: [4,5,6,10,12,13,14,15,16,17,18,19,20,21,22,23,24,25,26,27]
     AvailableSPIChannels: {'CE1'}                       
        AvailableI2CBuses: {'i2c-0','i2c-1'}             
         AvailableWebcams: {}                            
              I2CBusSpeed: 100000                        
   AvailableCANInterfaces: {"can0"}                      
   
     Supported peripherals

2. Create a connection to the PiCAN2 shield.

   ch = canChannel(raspiObj,"PiCAN2")

   ch = 
   
     Channel with properties:
   
          Interface: 'can0'
       ProtocolMode: 'CAN'
           BusSpeed: 500000
         SilentMode: 0
           Database: []
   
     Show all properties
   
   

   clear raspiObj ch

Create canChannel Object for PiCAN2 DUO Shield

1. Create a Raspberry Pi object.

   raspiObj = raspi("192.168.1.101","pi","raspberry")

   raspiObj = 
   
     raspi with properties:
   
            DeviceAddress: '192.168.1.101'                
                     Port: 18734                         
                BoardName: 'Raspberry Pi 3 Model B+'     
            AvailableLEDs: {'led0'}                      
     AvailableDigitalPins: [4,5,6,10,12,13,14,15,16,17,18,19,20,21,22,23,24,25,26,27]
     AvailableSPIChannels: {'CE1'}                       
        AvailableI2CBuses: {'i2c-0','i2c-1'}             
         AvailableWebcams: {}                            
              I2CBusSpeed: 100000                        
   AvailableCANInterfaces: {"can0", "can1"}                      
   
     Supported peripherals

2. Create a connection to the PiCAN2 DUO shield.

   ch = canChannel(raspiObj,"PiCAN2 DUO")

   ch = 
   
     Channel with properties:
   
          Interface: 'can1'
       ProtocolMode: 'CAN'
           BusSpeed: 500000
         SilentMode: 0
           Database: []
   
     Show all properties
   
   

   clear raspiObj ch

Create canChannel Object for can0 Interface

1. Create a Raspberry Pi object.

   raspiObj = raspi("192.168.1.101","pi","raspberry")

   raspiObj = 
   
     raspi with properties:
   
            DeviceAddress: '192.168.1.101'                
                     Port: 18734                         
                BoardName: 'Raspberry Pi 3 Model B+'     
            AvailableLEDs: {'led0'}                      
     AvailableDigitalPins: [4,5,6,10,12,13,14,15,16,17,18,19,20,21,22,23,24,25,26,27]
     AvailableSPIChannels: {'CE1'}                       
        AvailableI2CBuses: {'i2c-0','i2c-1'}             
         AvailableWebcams: {}                            
              I2CBusSpeed: 100000                        
   AvailableCANInterfaces: {"can0"}                      
   
     Supported peripherals

2. Create a connection with the can0 interface.

   ch = canChannel(raspiObj,"can0")

   ch = 
   
     Channel with properties:
   
          Interface: 'can0'
       ProtocolMode: 'CAN'
           BusSpeed: 500000
         SilentMode: 0
           Database: []
   
     Show all properties
   
   

   clear raspiObj ch

Set Properties of CAN Channel for PiCAN2 Shield

1. Create a Raspberry Pi object.

   raspiObj = raspi("192.168.1.101","pi","raspberry")

   raspiObj = 
   
     raspi with properties:
   
            DeviceAddress: '192.168.1.101'                
                     Port: 18734                         
                BoardName: 'Raspberry Pi 3 Model B+'     
            AvailableLEDs: {'led0'}                      
     AvailableDigitalPins: [4,5,6,10,12,13,14,15,16,17,18,19,20,21,22,23,24,25,26,27]
     AvailableSPIChannels: {'CE1'}                       
        AvailableI2CBuses: {'i2c-0','i2c-1'}             
         AvailableWebcams: {}                            
              I2CBusSpeed: 100000                        
   AvailableCANInterfaces: {"can0"}                      
   
     Supported peripherals

2. Create a connection to the PiCAN2 shield and set the channel properties.

   ch = canChannel(raspiObj,"PiCAN2","BusSpeed",250e3,"SilentMode",true)

   ch = 
   
     Channel with properties:
   
          Interface: 'can0'
       ProtocolMode: 'CAN'
           BusSpeed: 250000
         SilentMode: 1
           Database: []
   
     Show all properties
   
   

   clear raspiObj ch

Set Properties of can0 Interface Channel

1. Create an Raspberry Pi object.

   raspiObj = raspi("192.168.1.101","pi","raspberry")

   raspiObj = 
   
     raspi with properties:
   
            DeviceAddress: '192.168.1.101'                
                     Port: 18734                         
                BoardName: 'Raspberry Pi 3 Model B+'     
            AvailableLEDs: {'led0'}                      
     AvailableDigitalPins: [4,5,6,10,12,13,14,15,16,17,18,19,20,21,22,23,24,25,26,27]
     AvailableSPIChannels: {'CE1'}                       
        AvailableI2CBuses: {'i2c-0','i2c-1'}             
         AvailableWebcams: {}                            
              I2CBusSpeed: 100000                        
   AvailableCANInterfaces: {"can0"}                      
   
     Supported peripherals

2. Create a connection with the can0 interface and set the channel properties.

   ch = canChannel(raspiObj,"can0","BusSpeed",250e3,"SilentMode",true)

   ch = 
   
     Channel with properties:
   
          Interface: 'can0'
       ProtocolMode: 'CAN'
           BusSpeed: 250000
         SilentMode: 1
           Database: []
   
     Show all properties
   
   

   clear raspiObj ch

Tips

• If you cannot create a canChannel object, the canchannel object creation fails, check if the CAN interface is connected to the internet.

  To check if the CAN interface is connected to the internet, type the following command in the MATLAB command window.

  raspiObj.openShell

  In the Raspberry Pi terminal, type this command.

   $ ifconfig

  You can check for can0 presence in all Raspberry Pi boards. For PiCAN2 Duo, you can check if can1 is in the output. If present, execute the following command in the Raspberry Pi terminal and then recreate the canchannel object in MATLAB.

  r.system(' sudo ip link set can0 down type can');

• To troubleshoot PiCAN2, PiCAN2 Duo, and PiCAN3 shields, see here.

Extended Capabilities

C/C++ Code Generation

Generate C and C++ code using MATLAB® Coder™.

• You can deploy canchannel function on the Raspberry Pi hardware.

• To generate C/C++ code for this object and its associated functions, you must have an Embedded Coder license. For more information on selecting the right product stack according to your development goals, see Product Stack for Raspberry Pi Blockset.

Version History

Introduced in R2021b