Implementing CAN and CAN FD using the TCAN4550 System Basis Chip. In this presentation, we will briefly review the differences between CAN and CAN FD, and then review some CAN and CAN FD configurations in existing systems today. We'll then talk about how to implement CAN with the TCAN4550, as well as upgrading to CAN FD with the TCAN4550. We'll also review port expansion for both CAN and CAN FD interfaces and review the key takeaways.

Controller Area Network, often referred to as classic CAN, is a standard that defines both a protocol and a physical layer for asynchronous, serial communication in multi-point bus applications. Each node consists of a CAN transceiver and a CAN controller. The CAN controller is often integrated into the microcontroller. Communication occurs over a differential bus at up to 1 megabit per second for classical CAN or higher rates for CAN FD.

CAN Flexible Data Rate, referred to as CAN FD, allows for increased bus efficiency, providing data rates up to 5 megabits per second, while also increasing the payload size to 64 bytes. CAN FD does not require new connectors or cables, but does require an updated processor with CAN FD controller and associated CAN FD transceiver. While CAN FD adoption is accelerating, the integration of CAN FD controllers is limited. Multi-chip solutions require larger bombs and circuit boards, which result in higher transition costs.

As mentioned previously, CAN and CAN FD controllers cannot coexist on the same bus. With today's limited microprocessor support for CAN FD, the only way to realize CAN FD is to use an external, discrete CAN FD controller and associated transceiver, or possibly use a microcontroller that's oversized for the application. If any of the CAN nodes in the network are a classic CAN controller, the data rate will be capped at 1 megabit per second with an 8-byte payload.

Adding CAN FD to a system is simple and easy using the fully integrated controller and transceiver of the TCAN4550. By connecting to a microprocessor via a standard SPI interface, the TCAN4550 preserves existing hardware and software architectures, while allowing data rates up to 5 megabits per second and payload expansion up to 64 bytes per packet. It can also enable overall system cost reduction by allowing simpler microcontrollers to be used. Due to its direct battery connection, the device also allows for nodal power control via its inhibit pin.

There are also other SBC features that system designers can take advantage of, such as a watchdog timer, LDO output, and 1.8 volt I/O voltage support. All of these features are packed into a small PCB area that is 30% smaller than competition, which requires a two-chip solution. It should also be noted that the TCAN4550 has support for classic CAN and CAN FD, depending on the application, which can be automotive or industrial.

The TCAN4550 can also be used to add more classic CAN or CAN FD interfaces in systems with limited integrated CAN or CAN FD controllers in the microprocessor, allowing for multiple buses to be controlled via one software stack. The TCAN4550 SBC can implement classic CAN and CAN FD in systems where the MCU has no integrated controller, enabling both port and bus expansion. There is only a slight configuration difference needed to enable CAN FD versus classic CAN.

In closing, the TCAN4550 is a single, fully-integrated solution to fit many needs. With many integrated features to e-system design, such as a watchdog timer, LDO output, and wide I/O voltage support, it can quickly and easily be integrated into any automotive or industrial application. For more information, please visit TI.com.