TMS320F280049: How to get the data length of CAN receiving frame

The data length of CAN frame sent by the sender is not fixed, when the CAN module of f280049 receives data, is there a register that can observe the length of the received data frame?

DLC field in IF1MCTL register has this information. 

after initializing the received frame length to 4 bytes, data exceeding 4 bytes can still be received. Is this initialization meaningless?

DLC field of a Receive mailbox is a "don't care". Initializing that field is indeed meaningless.

Hi FF,

The data length is defined by the transmitting node.  If you are using C2000Ware, the function CAN_setupMessageObject() for the transmitting node will define this.  The last argument of this function define the number of bytes to be transmitted, which is a maximum of 8.

The register CAN_IFxMCTL also has a bit field called DLC which contains the data length information for the received frame at reception.  To poll this register, make  sure to note which IFx (1 or 2 is used by the rx node) and run the function CAN_transferMessage() to transfer the message object information including DLC to the IFxMCTL register.

Regards,

Joseph