Open search

White paper

CAN FD and the CRC issue

Dr. Arthur Mutter from Bosch has written a white paper about the CRC weaknesses in the original CAN FD protocol. The paper describes in detail the technical background and the solutions.

(Photo: Robert Bosch)

DURING THE STANDARDIZATION PROCESS IN THE ISO, several experts detected some CRC issues in the CAN FD protocol. The responsible ISO Task Force discussed the problems and proposed a solution. The agreed improvements are already part of the ISO 11898-1 document submitted for DIS (Draft International Standard) balloting. Bosch has written a white paper explaining the CRC weaknesses and the solutions developed within the ISO Task Force.

The paper discusses in detail bit-flip faults and faults caused by shortening or lengthening of bit sequences. It includes also exemplary cases demonstrating the CRC issue. In the solution chapter, the stuff-bit counter and the related parity bit are introduced. This paper provides the technical background, why and how the CAN FD frame format has been changed.

Publish date