CAN vs UART: what are the differences between the two communication modes?

Driven by growing demand for alternative, more sustainable mobility solutions, the electric bike industry is booming. This development is accompanied by a proliferation of peripherals that need to be integrated into bikes, such as GPS units, sensors, brakes and so on.

While this increase in complexity brings significant added value for the end user, it also poses a major challenge: that of ensuring fluid, efficient communication between all these elements.

This is where communications protocols such as CAN and UART play a key role. These digital languages enable the various components of the electric bike to talk to each other, exchange data and synchronise their actions. But which to choose? CAN or UART?

In this article, discover the subtle differences between these two modes of communication.

The UART communication mode, a sure value for connected objects

Long used in the bicycle industry, the UART is a ‘point-to-point’ communication protocol. The way it works is based on a private connection with another electronic component. This means that each device to which it is connected can send and receive information instantaneously and independently, guaranteeing fluid, responsive communication.

Quels sont les avantages du mode de communication UART

Le mode de communication UART présente 3 avantages majeurs :  

  • Simplicity and low cost: UART stands out for its simplicity of implementation and low cost, making it accessible for less complex systems such as simple data transmission between a sensor and a display.
  • Efficient point-to-point communication: Designed for simple integration, UART excels at direct communication between two devices. Its simple, straightforward design enables data to be transmitted quickly and reliably between the connected peripherals.
  • Widespread operation: UART is a mature and widely used protocol, present in many microcontrollers and electronic peripherals. This widespread adoption facilitates the integration of compatible components and simplifies the development of UART-based systems.

However, faced with increasingly comprehensive and therefore complex systems, the UART is showing its limitations, particularly for e-bikes which incorporate more modern integrations.

What are the limits of the UART communication mode? 

  • Limited scalability: The UART is designed for point-to-point communication between two devices. If you want to connect more devices, you need to set up several separate UART links with new cables for each component, which makes system management much more complex.
  • Complex priority management: In a multi-component system with several UART devices, message priority management becomes a major challenge. The UART has no built-in mechanism for arbitrating communication conflicts, which can lead to data loss or system malfunctions.

  • Lack of robustness: The UART is sensitive to electromagnetic interference (EMI) and electrical noise, which can affect the reliability of communication. This sensitivity is particularly problematic in noisy environments such as urban areas or rough paths.
  • Limited scalability: The UART is not designed for scalable systems or frequent peripheral upgrades. Adding new components or changing the network topology can require significant changes to cabling and code, inhibiting innovation and flexibility.

In view of these limitations, the CAN communicator mode opens up more possibilities by supporting more complex systems.

The CAN Protocol brings a breath of fresh air to the electric bike industry

Developed in the automotive industry, CAN (Controller Area Network) is gradually gaining ground. Its robustness, flexibility and ability to manage complex networks make it a major asset for tomorrow’s intelligent bicycles.

Unlike the UART, the CAN protocol allows multiple connections between different components. It is based on the BUS, a communication network that enables all connected devices to exchange information, and can be visualised as a web where each node in the network can send and receive messages, promoting multidirectional and collaborative communication.

What are the advantages of the CAN protocol?

To this extent, this mode of communication offers several advantages:

  • Flexible communication: Unlike the UART, which limits communication to two devices, the CAN BUS enables all devices connected to the network to exchange information. This multi-master architecture offers greater flexibility and considerably simplifies system management.
  • Message prioritisation for smooth communication: CAN has an intelligent message prioritisation mechanism, ensuring that data identified as critical is transmitted first. This avoids communication conflicts and ensures smooth, reliable communication, even in complex systems with many peripherals.
  • Robust and resistant to interference: CAN is designed to operate in changing environments subject to electromagnetic interference (EMI). This robustness ensures high-speed communication with low latency, guaranteeing responsiveness and precise operation of the electric bicycle.

These advantages make CAN the obvious choice for modern e-bikes, which require reliable, high-performance and scalable communication to deliver an optimum user experience. Its ability to manage complex networks with numerous peripherals and guarantee fluid communication in real time makes CAN the spearhead of innovation in the electric bike industry.

What are the limits of the CAN protocol for E-bikes?

However, while the CAN protocol offers many advantages for modern electric bikes, it also has certain limitations that are important to bear in mind.

  • Complexity of implementation: CAN is a more complex protocol to implement than UART. It requires specific skills and knowledge of network communication.
  • Slightly higher cost: The components and development tools for CAN are generally more expensive than those for UART. This cost difference may be a factor to consider depending on the intended use. For simple systems with two or three peripherals, the additional complexity of CAN may not be justified. The UART may offer a simpler and more cost-effective solution in these cases.
  • Need for a dedicated controller: CAN requires a dedicated controller to manage the bus and arbitrate communication conflicts. This controller adds another element to the system architecture.

CAN vs UART: The verdict

The choice between CAN and UART will depend on the specific needs of each application. For simple two- or three-element systems, UART offers a cost-effective solution that’s easy to implement. However, for modern e-bikes with numerous peripherals and advanced features, CAN is the obvious choice. Its robustness, flexibility and ability to manage complex networks ensure smooth, efficient and reliable communication, which is essential for an optimum user experience.

In conclusion, the electric bike industry is undergoing a major technological transformation, driven by the adoption of CAN as the standard communication protocol. This development will make it possible to create intelligent bikes that are even more efficient, connected and safe, to meet the growing expectations of today’s and tomorrow’s cyclists.

Velco, the choice of CAN protocol for more complete integration 

In designing its Mobitrax premium IoT, Velco chose to integrate the CAN BUS protocol. Once connected to the electric bike and its system, it is capable of collecting a wide range of data which, once processed, can be used to offer a complete and differentiating experience to its users.