What is the difference between CAN 2.0 A and CAN 2.0 B ?

Title: What is the difference between CAN 2.0A and CAN 2.0B? A Comprehensive Guide

The Controller Area Network (CAN) protocol is a widely used communication protocol that has been widely adopted in various industries. It is used for transmitting data between electronic devices in a reliable and efficient manner. There are two common variants of the CAN protocol, namely CAN 2.0A and CAN 2.0B. Although they are similar, there are significant differences between them. This article will provide an easy-to-understand explanation of the dissimilarities between CAN 2.0A and CAN 2.0B.

CAN 2.0A: Standard Format

CAN 2.0A is the standard format of the CAN protocol. It has a defined data frame format that consists of a 29-bit ID, a 11-bit group identifier, and a 20-bit data field. The data field can hold up to 8 data bytes.

CAN 2.0B: Incremental ID

CAN 2.0B is an extension of the CAN 2.0A protocol that adds a new 11-bit field for Incremental ID. This field can hold up to 64 data bytes.

CAN 2.0A: Arbitration Field and Data Frame

In CAN 2.0A, the Arbitration Field is used for resolving conflicts between devices trying to access the same data. It is located at the end of the data frame and has a field for the highest bit.

In contrast, in CAN 2.0B, the Incremental ID field is used for resolving conflicts. It is located at the end of the data frame and has a field for the highest bit.

CAN 2.0A: Data Buffer

CAN 2.0A supports a data buffer, which allows for efficient data transfer between devices. A data buffer can hold up to 8 data bytes and is located after the arbitration field in the data frame.

CAN 2.0B: No Data Buffer

In contrast to CAN 2.0A, CAN 2.0B does not support a data buffer. Instead, it uses a separate field called the "" (Window Size) to determine the size of the data buffer.

CAN 2.0A: Multi-Address

CAN 2.0A supports Multi-Address, which allows devices to access multiple endings of the same data frame. Multi-Address is determined by the highest bit in the data frame.

CAN 2.0B: No Multi-Address

In contrast to CAN 2.0A, CAN 2.0B does not support Multi-Address. Instead, it uses a single endpoint for accessing the data.

CAN 2.0A: Self-healing

CAN 2.0A supports self-healing, which allows devices to recover from network failures. When a device fails, it sends a CAN message with a unique identifier to indicate the failure and the data it was carrying.

CAN 2.0B: No Self-Healing

In contrast to CAN 2.0A, CAN 2.0B does not support self-healing. Instead, it uses a different method for identifying failed devices.

Conclusion:

In conclusion, although CAN 2.0A and CAN 2.0B share similar features, they have significant differences. CAN 2.0A has a standard format, supports arbitration field and data frame, has a data buffer, and supports self-healing. On the other hand, CAN 2.0B has an incremental ID field, does not support self-healing, and has no data buffer. By understanding these differences, device manufacturers can select the appropriate variant of the CAN protocol for their applications.