CAN / CAN FD / CAN XL (2024)

FAQs

What is the difference between CAN FD and CAN XL? ›

CAN-FD allows for more flexible data rates and larger payloads, and CAN-XL goes further by supporting very high data rates, exceeding CAN-FD.

In Extended Format, this is a recessive bit. In Extended Format, the reserved bits r1 and r0 of Control Field are dominant bits. In CAN FD, the Data Field can contain from 0 to 64 bytes, as oppose to 0 to 8 bytes in Classical CAN. In CAN FD, the data can be transmitted at a higher bit rate.

Higher Data Rates: CAN XL supports data rates of up to 10 Mbps, providing even more bandwidth for your applications. Larger Payload Sizes: The increased payload capacity of up to 2048 bytes allows you to transmit more data in a single frame, making it ideal for applications that require high-resolution sensor data.

CAN XL is the 3rd generation controller-area network protocol, building on and supporting backward compatibility with Classic CAN and CAN FD networks. It is targeted at in-vehicle networks, connecting multiple controllers and sensors using a single differential-mode bus.

Vehicles currently using this faster CAN FD (CAN Flexible Data-Rate) protocol include many General Motors and Ford 2019 and 2020 vehicles. CAN FD is one of the newer communication protocols, noted for being faster, more reliable and more secure, Autel says.

Are CAN FD MCUs backwards compatible with CAN 2.0? Yes, CAN FD MCUs support both CAN 2.0 and CAN FD.

Developed by Bosch, CAN with Flexible Data-Rate (CAN FD) is an extension to the original CAN protocol as specified in ISO 11898-1 that responds to increased bandwidth requirements in automotive networks.

CAN FD enables you to increase data payloads 8x, from 8 bytes in classic CAN to 64 bytes. This increase requires only a small overhead in the rest of the frame while still resulting in much better data efficiency overall, as shown in Figure 1.

CAN/CAN FD can only support up to 1 Mbps-10Mbps of bus load, and the bandwidth support is very low. In contrast, Ethernet supports GBs and Tbs of busloads and higher bandwidths. But, CAN has negligible latency, and Ethernet lags in that.

CAN XL fast mode? ›

Fast Mode is applied only to the data phase of the CAN XL frame, as shown in Figure 3. Figure 3. Fast Mode is applied to the high-speed data phase of a CAN XL frame to enhance signal integrity.

The major difference between CAN and LIN is That CAN is a broadcast type of protocol, where each node can access the bus at any point in time. LIN is based on a master-slave type of communication; Where 1 Master node can communicate up to 15 slaves nodes.

CAN XL is standardized in the ISO 11898-1:2024 (CAN CC, CAN FD, CAN XL and CAN FD light). In addition, many other CAN related standards will be updated simultaneously to support CAN XL. Examples are the CAN Conformance Test according to ISO 16845 and the physical layer which is released as ISO 11898-2:2024.

Looking at the required processing time, it appears to be that 10BASE-T1S requires more CPU time than CAN XL to process the traffic on the bus. In fact, the same amount of processing time per payload is required. We see from the net-data rate that this is around 30% higher for 10BASE-T1S than for CAN XL.

CANopen is a "higher layer protocol" based on CAN bus.

This means that CAN bus (ISO 11898) serves as the 'transport vehicle' (like a truck) for CANopen messages (like containers). You can view CANopen from a 7-layer OSI model, see below.

The significant difference lies in the data rate that both of them offer. The Classical CAN offers 11-bit (standard) and 29-bit (extended) data rates, whereas CAN FD as the name suggests, offers flexible data rates, ranging from 0-64 bytes per frame.

The main difference in behavior when CAN-TP utilizes CAN-FD over CAN Classic is that the the data length and speed the message are increased over the CAN bus. Figure 1: Example CAN-TP message over a CAN bus.

CAN FD is an extension to the original CAN bus protocol. It was developed to meet the need to increase the data transfer rate (up to 5 times faster with CAN FD) and support larger message frame sizes for use in modern automotive Electronic Control Units (ECU) and many other industry applications.