[1] The basic idea to overclock part of the frame and to oversize the payload dates back to 1999.
[2] Developed in 2011 and released in 2012 by Bosch, CAN FD[3] was developed to meet the need to increase the data transfer rate up to 5 times faster and with larger frame/message sizes for use in modern automotive Electronic Control Units.
As in the classical CAN, CAN FD protocol is designed to reliably transmit and receive sensor data, control commands and to detect data errors between electronic sensor devices, controllers and microcontrollers.
Although CAN FD was primarily designed for use in high performance vehicle ECUs, the pervasiveness of classical CAN in the different industries will[citation needed] lead into inclusion of this improved data-communication protocol in a variety of other applications as well, such as in electronic systems used in robotics, defense, industrial automation, underwater vehicles, medical equipment, avionics, down-hole drilling sensors, etc.
Using CAN FD, Electronic Control Units (ECUs) are enabled to dynamically switch between different data rates and longer or shorter messages.
Commands issued by the executing ECU software reach the output controller much faster.
Additionally, arbitration data rates are limited to 1 Mbit/s to maintain compatibility with classical CAN devices.
The CAN FD protocol specification provides improved error detection[4] in received CAN messages and enhanced flexibility of data transfer speeds to account for differences in sensor polling rates.
All versions of the CAN protocol are designed with robust collision resolution that depends on signal propagation time, network topology, and the number of units on the bus.
{\displaystyle \textstyle T_{s}=\left({\frac {\left({\text{SOF}}+{\text{ID}}+r1+{\text{IDE}}+{\text{EDL}}+r0+{\frac {\text{BRS}}{2}}+{\frac {\text{CRCdel}}{2}}\right)\cdot 1.2}{t_{x}}}\right)+{\frac {{\text{ACK}}+{\text{DEL}}+{\text{EOF}}+{\text{IFS}}}{t_{x}}}}
Here 1.2 is taken to be the factor of the worst case bit stuffing,[7] which means the computation shall be increased by 25%.
It is considered BRS and CRCdel divided by 2, because they are exactly in the shift of bit rate transition.
CAN FD also has decreased the number of undetected errors through increases in the performance of the CRC-algorithm.
[9] CAN FD bit rate can be up to 8 Mbit/s with the right CAN SIC (Signal Improvement Capability) Transceiver and so up to 8 times faster than classical CAN with 1 Mbit/s data phase.
Due to higher communication speed, CAN FD constraints are tougher in terms of line parasitic capacitance.
[10] Despite a higher stand-off voltage≤ (37 V), devices for truck applications must also comply with the low capacitance requirement (3.5 pF).
The above table explains the transfer protocol defined for CAN + CANFD, based on ISO 15765-2 (ISO-TP), used for sending packets of data longer than what fits in a CAN frame.
Additionally there are new CAN SiC (Signal improvement Capability) Transceiver with 5 to 8 Mbit/s data rate.
[13] Some of the companies behind the new standard include STMicroelectronics, Infineon,[14] NXP, Texas Instruments, Kvaser, Daimler and GM.