CAN Receive

Receive messages from the controller area network (CAN) bus

Since R2021b

Add-On Required: This feature requires the MATLAB Coder Support Package for NVIDIA Jetson and NVIDIA DRIVE Platforms add-on.

• 

Libraries:
NVIDIA Jetson and NVIDIA DRIVE / Communication

Description

The CAN Receive block receives messages from the CAN bus through the time triggered CAN (TTCAN) controller available on NVIDIA^® embedded boards. This block uses the SocketCAN interface to communicate with the CAN controller hardware on NVIDIA boards.

You can also use this block to interact with a virtual CAN interface. A virtual CAN interface allows transmission and reception of CAN frames without a native CAN interface associated with real hardware. For more information on how to set up a virtual CAN interface, see Setup Virtual CAN Interface.

The CAN Receive block supports Raw data and CAN Msg as output types. To use CANdb (CAN database) file or to specify signals manually, use CAN Msg output type and CAN Unpack block. The CAN Unpack block is available from the Vehicle Network Toolbox™.

Examples

CAN Bus Communication on NVIDIA Jetson TX2 in Simulink

Deploy a Simulink® model that uses CAN communication for a deep learning application. The Simulink model in this example uses the CAN Transmit and CAN Receive blocks from the MATLAB® Coder™ Support Package for NVIDIA® Jetson® and NVIDIA DRIVE® Platforms to model a CAN bus system on the Jetson TX2 platform. The model uses the CAN bus to transmit the recognized traffic sign objects in a video frame from one CAN node to another CAN node.

• Open Live Script

Ports

Output

Data — Message data port

vector | scalar

Received message data, returned as a vector or scalar.

If Data to be output as is set to Raw data, the received message data is an 1-by-N array of type uint8.

If Data to be output as is set to CAN Msg, the data port is renamed to CAN Msg and the received message data is output as a Simulink^® bus signal. To extract data from Simulink bus signal, use the CAN Unpack block from Vehicle Network Toolbox.

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	RXWAR	RXEP	RX0OVR	RX1OVR
bit7	bit6	bit5	bit4	bit3	bit2	bit1	bit0

RX1OVR: Receive Buffer 1 Overflow Flag bit

RX0OVR: Receive Buffer 0 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 — CAN interface name

can0 (default) | valid device name

Specify the name of the real or virtual CAN interface to use.

Set up CAN interface — Bring up CAN interface

off (default) | on

Select this parameter to bring up the CAN interface on the NVIDIA target before receiving CAN frames.

CAN interface type — Type of CAN interface

Real (default) | Virtual

Select the type of CAN interface.

• If the CAN interface type is Real, set this parameter to Real. Setting this parameter to Real would not bring up the CAN interface in these scenarios.

  • The interface is already brought up on the target with a CAN-Bus Speed that does not match with the CAN Bus Speed (kBit/s) parameter. The block would not transmit the CAN frames. Bring the existing interface down before enabling this parameter.

  • If the interface is already brought up on the target with the CAN-Bus Speed that matches with the CAN Bus Speed (kBit/s) parameter. The block will transmit the CAN frames.

• If the CAN interface type is Virtual, set this parameter to Virtual.

Dependencies

To enable this parameter, select Set up CAN interface.

Data to be output as — Data output type

Raw data (default) | CAN Msg

Data type used for receiving messages.

Identifier Type — Message identifier type

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

Message identifier type.

Dependencies

To enable this parameter, set Data to be output 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 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

To enable this parameter, set Data to be output as to Raw data.

Message Length — Length of message

8 (default) | positive integer

Message length.

Dependencies

To enable this parameter, set Data to be output as to Raw data.

Sample time (seconds) — Time frequency at which block receives data

0.1 (default) | scalar

Specify how often the block should read the port buffer. Enter a value greater than 0 or -1 (for inherited sample time).

When you specify this parameter as-1, Simulink determines the best sample time for the block based on the block context within the model.

This value defaults to a sample time of 0.1 seconds. Smaller values require the processor to complete the same number of instructions in less time and this can cause task overruns.

Output Error — Output error codes

off (default) | on

Select to output error codes if the message transfer fails.

Output Remote — Enable remote messages

off (default) | on

Select to output remote messages.

Tips

• If a Simulink model contains CAN Transmit and CAN Receive block, and the Set up CAN interface is set only on the CAN Transmit block, then a CAN receive socket might not be set up because of the order of execution of the blocks. In such cases, manually set up the CAN interfaces before executing the models or enable Set up CAN interface on all blocks.

Version History

Introduced in R2021b