CAN Receive

Receive message from CAN network

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Libraries:
Raspberry Pi Blockset / Communication

Description

The CAN Receive block receives messages from the CAN network. This block uses SocketCAN which is a device-independent driver for implementing the CAN interface supporting all CAN shields.

The CAN Receive block supports Raw data and CAN Msg as output types. To use a CANdb (CAN database) file or to specify signals manually, use CAN Msg output type and the CAN Unpack (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 Receive 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

Output

Data — Message data port

vector | scalar

Received message data, returned as a vector or scalar.

Data Types: uint8 | CAN Msg

Status — Status of output message

scalar

Status of the received output message.

Data Types: uint8

Error — Error codes

scalar

Error codes.

Dependencies

To enable this parameter, select Output Error.

00	00	00	00	00	RXWAR	RXEP	RXOVR
bit7	bit6	bit5	bit4	bit3	bit2	bit1	bit0

RXOVR: Receive Buffer Overflow Flag bit

RXEP: Receive Error-Passive Flag bit

RXWAR: Receive Error Warning Flag bit

Remote — Remote message flag

scalar

Remote message flag.

Dependencies

To enable this parameter, select Output Remote.

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 properties.

Data to be output as — Data output type

Raw data (default) | CAN Msg

Select a type to receive message.

• Raw data – To receive message as a 1-by-N uint8 array, select Data to be output as as Raw data.

• CAN Msg – To receive message in CAN message format, select Data to be output as as CAN Msg and then perform these steps:

  1. Add a CAN Unpack (Embedded Coder) block to your Simulink^® model.

  2. Connect the output of the CAN Receive block to the input of the CAN Unpack (Embedded Coder) block.

  3. Using the options in the Data to be output as list of the CAN Unpack (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 Unpack (Embedded Coder) inherits the message properties from the uploaded file.

Identifier Type — Message identifier type

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

The type of message identifier.

Dependencies

This parameter appears only when you select Data to be output as as 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 size or 29 bits long for the extended frame size, 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

This parameter appears only when you select Data to be output as as Raw data. To output the identifier of the CAN Msg, select Output identifier of the CAN Unpack (Embedded Coder) block.

Message Length — Length of message

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

The length of the message, in bytes.

Dependencies

This parameter appears only when you select Data to be output as as Raw data. To output the length of the CAN Msg, select Output length of the CAN Unpack (Embedded Coder) block.

Sample Time — Time interval to read message

0.1 (default) | -1 | nonnegative real value

Specify how often the block receives message, in seconds. When you specify this parameter as -1, Simulink determines the best sample time for the block based on the block context within the model.

Output Error — Error in received message

off (default) | on

When you select the Output Error parameter, the block configures an output port, Error. The port outputs the error code as a uint8 integer. Each bit in code corresponds to the type of error in the received message. An output of 0 indicates that the message is error-free. Any value other than 0 indicates that the message is an error frame.

Dependencies

This parameter appears only when you select Data to be output as as Raw data. To output the error in the CAN Msg, select Output error of the CAN Unpack (Embedded Coder) block.

Output Remote — Enable remote messages

off (default) | on

Select this parameter to enable the Remote output port. This port outputs the message remote frame status.

Dependencies

To enable this parameter, set Data to be output 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