CAN Transmit

Transmit message to CAN network

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Libraries:
Raspberry Pi Blockset / Communication

Description

The CAN Transmit block transmits messages to the CAN network. This block uses SocketCAN which is a device-independent driver for implementing the CAN interface supporting all CAN shields.

The CAN Transmit block supports Raw data and CAN Msg as input types. To use a CANdb (CAN database) file or to specify signals manually, use CAN Msg input type and the CAN Pack (Embedded Coder) block.

For more information on how to enable the SPI interface and configure the MCP2515 CAN controller for CAN communication, see Enable and Configure Raspberry Pi for SPI and CAN Communication Using MCP2515 CAN Controller.

You can use CAN Transmit block to interact with a real or virtual CAN interface. To bring up the CAN interface with Raspberry Pi^®, refer to the user guide of your CAN shield. For more information on how to set up a virtual CAN interface, see Setup Virtual CAN Interface.

Note

To generate code C/C++ code for this block, you must have an Embedded Coder^® license.

Examples

Transmit and Receive Data Using Raspberry Pi CAN Blocks

To use Raspberry Pi® Blockset to transmit and receive data from the CAN network using the specified CAN device.

• Open Model

Monitor Engine RPM Using Raspberry Pi CAN Blocks

Use Raspberry Pi® Blockset to monitor vehicle engine RPM and read the data on a web browser.

• Open Model

Log CAN Bus Data on Raspberry Pi

Use Raspberry Pi® Blockset to monitor a controller area network (CAN) bus, perform basic CAN conversions, and log CAN data in a measurable data format (MDF) file. This example also showcases the inter-operability between a model deployed in Simulink® and a Python® program running simultaneously on Raspberry Pi hardware.

• Open Model

Ports

Input

Port1 — Message data

vector | scalar

The block accepts messages in Raw data and CAN Msg formats.

• Raw data — To accept the message as a uint8 vector array, set Data is input as to Raw data.

• CAN Msg — To accept the message in CAN message format, set Data is input as to CAN Msg.

Data Types: uint8 | CAN Msg

Output

Port1 — Status of data transmission

scalar

Output port to display status of data transmission. For more information, see Output Status.

Dependencies

To enable this port, select the Output Status parameter.

Parameters

CAN interface — Name of CAN interface

can0 (default) | char

Enter the name of the real or virtual CAN interface. To find the name of the CAN interface, in the Raspberry Pi terminal, execute the ifconfig command. To configure the CAN interface, see CAN.

Data is input as — Data input type

Raw data (default) | CAN Msg

Data input type used for transmitting messages.

• Raw data — To accept the message as a uint8 vector array, set Data is input as as Raw data.

• CAN Msg — To accept the message in CAN message format, set Data is input as as CAN Msg and then perform these steps:

  • Add a CAN Pack (Embedded Coder) block to your Simulink^® model.

  • Connect the output of the CAN Pack (Embedded Coder) block to the input port of the CAN Transmit block.

  • Using the options in the Data is input as list of the CAN Pack (Embedded Coder) block, specify if you want to create your messages or you want to upload a CAN database file. If you choose to upload a CAN database file, the CAN Pack (Embedded Coder) inherits the message properties from the uploaded file.

Wait until data sent — Wait until data is sent

off (default) | on

When selected, the block waits for the time specified in the Time out in seconds parameter before transferring data.

• on — When you select this parameter, the block operates in the Blocking mode. If the message received in the previous time step is sent, the block accepts message from the input port. If the send operation is in progress, the block waits for the time specified in the Time out in seconds parameter, and then it accepts message from the input port.

  A task overrun occurs if the target hardware is still waiting for the requested message to be sent when the next send operation is scheduled to begin. To fix overruns:

  • Increase the sample time of input message.

  • Reduce the length of message at the input port.

• off — When you clear this parameter, the block operates in the Non-blocking mode. If the transmission of the message received in the previous time step is still in progress, the message at the input port at the given time step is dropped.

Time out in seconds — Waiting time for sending data

1 (default) | integer

Specify the wait time for sending the message. After the specified time, the block times out.

Dependencies

To enable this parameter, select Wait until data sent.

Output Status — Output status of message transfer

off (default) | on

Select this option to indicate the status of message transfer. Status port outputs 0 for successful transmit and error codes in case of failure. Error codes are listed in this table.

00	00	ABTF	MLOA	TXERR	TXBO	TXEP	TXWAR
bit7	bit6	bit5	bit4	bit3	bit2	bit1	bit0

ABTF: Message Aborted Flag bit

MLOA: Message Lost Arbitration bit

TXERR: Transmission Error Detected bit

TXBO: Bus-Off Error Flag bit

TXEP: Transmit Error-Passive Flag bit

TXWAR: Transmit Error Warning Flag bit

Identifier Type — Message identifier type

Standard (11-bit identifier) (default) | Extended (29-bit identifier)

Message identifier type.

Dependencies

To enable this parameter, set Data is input as to Raw data.

Message ID — Message identifier

100 (default) | numeric identifier of length 11 or 29 bits

Message identifier, which is 11 bits long for the standard frame or 29 bits long for the extended frame, specified in decimal, binary, or hex. For binary and hex formats, use bin2dec(' ') and hex2dec(' '), respectively, to convert the entry. The message identifier is coded into a message that is sent to the CAN bus.

Dependencies

To enable this parameter, set Data is input as to Raw data. For CAN Msg, the message identifier is inherited from the identifier specified in the CAN Pack (Embedded Coder) block.

Message Length — Value of message length

8 (default) | positive integer less than or equal to 8

The length of the message, in bytes.

Dependencies

To enable this parameter, set Data is input as to Raw data. For CAN Msg, the message length is inherited from the length of the CAN Pack (Embedded Coder) block.

Request Remote Frame — Enable remote message

off (default) | on

When you select this parameter, the remote frame of the message is set to 1 indicating that the block is requesting the transmission of a specific identifier.

Dependencies

To enable this parameter, set Data is input as to Raw data.

Extended Capabilities

C/C++ Code Generation

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

To generate code C/C++ code for this block, 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 R2019b