F2838x-M4 MCAN Receive

Read data from CAN bus

Since R2021a

• 

Libraries:
C2000 Microcontroller Blockset / F2838x / M4

Description

The MCAN Receive block reads messages from a Controller Area Network (CAN) connected to the hardware.

In the Unpacked mode, the block outputs different fields of unpacked CAN Messages.

In the Packed mode, the block outputs a Simulink^® bus signal. To extract data from the Simulink bus signal, connect it to a CAN-FD Unpack block.

The MCAN Receive block receives messages from the CAN and delivers them to the Simulink model. It outputs one message or all messages at each time step, depending on the block parameters. The MCAN Receive block stores CAN messages received from the bus in a first-in, first-out (FIFO) or buffer. The FIFO or buffer delivers the messages to your model in the queued order at every time step.

Note

• For MCAN Receive block, if the data is not available, the output status shows the previously received data.

• When the Output type is packed and MCAN Receive block is connected to CAN FD Unpack block, the values of the error, error state indicator (ESI), reserved, and timestamp fields of the received message are set to 0 and these values are reflected on the output of CAN FD Unpack block.

In receive output status we should mention the current behavior when data is not available. The output data will be retained to its previously received value in case of data is not available.

The number of elements to be stored in FIFO is configured in configuration parameters. In case of buffers, the new data will not be stored unless the old data is read.

The FIFO, blocking or overwrite mode settings are configured in the MCAN.

Specify the Output type and its properties using the block parameters dialog box. Configure additional properties of the CAN module in the Configuration Parameters. For more refer to Model Configuration Parameters for Texas Instruments F2838x (ARM Cortex-M4).

Ports

Output

Msg — CAN Message

vector | scalar

The MCAN Receive block outputs the received CAN message (data and header) the Simulink bus signal. The CAN message received from the bus will be stored in a FIFO or buffer.

Dependencies

To enable this port, set Output type to Packed.

Data Types: CAN Msg

Data — Message data

vector | scalar

The block outputs data from the received CAN message. The maximum size of the data is 64 of uint8 format.

Dependencies

To enable this port, set Output type to Unpacked.

Data Types: uint8

Status — Status of received message

scalar

The port outputs the message read status. The block outputs the status as 0 if it reads new message and 1 if it does not.

Dependencies

To enable this port select the Output Status parameter.

Data Types: uint8

CAN identifier(ID) — CAN message identifier

scalar

The port outputs a standard or extended from the received CAN message.

Dependencies

To enable this port, set Output type to Unpacked.

Data Types: uint32

Length(LEN) — CAN message length

scalar

The port outputs the length of the received CAN message in bytes.

Dependencies

To enable this port, set Output type to Unpacked.

Data Types: uint8

Remote transmission request(RTR) — Remote frame status

scalar

The port outputs the remote transmission status as one of these values.

• 1 - if the received CAN message is a remote frame

• 0 - if the received CAN message is a data frame

Dependencies

To enable this port, set Output type to Unpacked.

Data Types: uint8

Bit rate switch(BRS) — Bit rate switch status

scalar

The port outputs:

• 0 - when CAN FD frames are transmitted without bit rate switching

• 1 - when CAN FD frames are transmitted with bit rate switching

Dependencies

To enable this port, set Output type to Unpacked.

Data Types: uint8

Extended identifier(XTD) — Extended or standard identifier

scalar

The port outputs:

• 0 - if its 11-bit standard identifier

• 1 - if its 29-bit extended identifier

Dependencies

To enable this port, set Output type to Unpacked.

Data Types: uint8

Frame data format(FDF) — CAN frame data format

scalar

The port outputs the CAN frame data format as:

• 0 - Classic CAN

• 1 - CAN-FD

Dependencies

To enable this port, set Output type to Unpacked.

Data Types: uint8

Parameters

Read source — CAN receive message source

Buffers (default) | FIFO 0 | FIFO 1

The CAN message received from the bus will be stored in FIFO or buffer.

The MCAN Receive block stores the message in a FIFO0, FIFO1 or buffer depending on the filter configuration you set in the hardware configuration parameters.

Buffer number (0-63) — Buffer number

0 (default) | 1 | 2...

Specify the number of the buffer in which you want the MCAN Receive block to store the received CAN message.

Dependencies

To enable this parameter, set Read source to Buffers.

Output Type — Message output type

Packed (default) | Unpacked

The output type of the MCAN Receive block is either Packed or Unpacked.

In the Unpacked mode, the block outputs the different fields of unpacked CAN message. In the unpacked mode, the MCAN Receive block has 7 (ID, XTD, FDF, BRS, LEN, RTR, Data) output ports.

In the Packed mode, the block outputs a Simulink bus signal. To extract data from Simulink bus signal, connect it to the CAN-FD Unpack block.

Output Status — Enable output status

off (default) | on

When you select the Output Status parameter, the block configures the Status output port. The port outputs the read status.

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.

Version History

Introduced in R2021a