Switching Bit Rates

With the CAN protocol version established as CAN XL, it’s time to switch to the data phase bit rate. Not only will the bit rate rise, but the communication will switch the CAN XL SIC drivers to a push-pull mode from dominant-recessive.

For CAN FD, the bit rate switch happens in the BRS bit at the sample point. Due to there being a small gap of time between the FDF bit and the BRS bit, you can end up with a clock variation offset which can make knowing where the data bit starts uncertain. In CAN XL, there is now a second recessive to dominant edge to synchronize the data bit sample point to resolve this uncertainty.