SLLSFS2 September 2025 TCAN6062-Q1
ADVANCE INFORMATION
CAN XL introduces an additional drive state to the CAN transceiver for use during the data phase of a CAN frame. After the arbitration phase has concluded and a single node has won priority of the CAN bus there is no longer risk of multiple devices trying to simultaneously drive contending drive states. CAN XL takes advantage of this by switching the driver to a push-pull driver architecture during the data phase of the CAN frame. The FAST TX mode driver has two strongly driven drive states as opposed to only the single strong dominant drive state of the SIC mode driver. This allows much higher data rates to be used during the data phase compared to typical CAN HS or CAN FD.
For the transceiver to change drive states into FAST TX mode a PWM signal is driven on the TXD pin by the CAN XL controller. Depending on the duty cycle of this PWM signal the driver outputs either a Level_0 or Level_1 state which correspond to logic 0 and logic 1 states respectively. The timing of the TXD signal required to change driver modes is detailed further in Section 7.3.3.3.
The CAN XL FAST mode uses differential logic thresholds that are different than those used by CAN FD and CAN SIC transceivers. This means that an additional FAST mode receiver is needed, so that FAST TX mode drive states can be decoded. For the device receiver to switch between SIC mode and FAST RX mode a PWM signal is driven on the TXD by the receiving CAN XL controller. This is uniquely different from standard CAN which has the TXD signal of all receiving nodes remain high during the data phase of a received frame. The timing of the TXD signal required to change receiver modes is detailed further in Section 7.3.3.2.
An out of bounds (OOB) comparator is used to indicate when a CAN XL drive state is detected on the CAN bus while the device is in SIC mode and FAST RX mode is not active. See Section 7.3.4 for details.