Reason behind CAN Data Bytes limited to 8 bytes

[pranavpathak]

Dear all,

Can anyone please explain the reason behind limiting the CAN Data Bytes in a message to 8 bytes, even if length of DLC field is 4 bit which can be used to transmit 16 bytes of data ? Is there any specific reason behind this ? can frame can bus can networks can driver

Thanks,

Pranav

[PetrS]

Hi,

It was probably enough in past and it made a space for further expansions. It was standardized in this way and all MCUs just follow this CAN 2.0A/B specifications. Many controllers allow the transmission and/or reception of a DLC greater than eight, but the actual data length is always limited to eight bytes.

Some reserved bits, unused DLC codes plus new bits in Control field are used in CAN FD specification to allows the extended payload up to 64 bytes, and have the ability to send the payload with higher data rates, see e.g. http://www.can-cia.org/can-knowledge/can/can-fd/

BR, Petr