Serial buses are pervasive in today’s digital designs and are used for a variety of purposes including on-board chip-to-chip communication, CPU to peripheral control, as well as for remote sensor data transfer and control. Without intelligent oscilloscope serial bus triggering and protocol decode, it can be difficult to debug these buses and correlate data transfers with other mixed signal interactions in your system. Keysight’s InfiniiVision X-Series and Infiniium Series oscilloscopes (DSOs) and mixed-signal oscilloscopes (MSOs) offer optional integrated serial bus triggering and hardware-based protocol decoding solutions that give you the tools you need to accelerate debug of your designs that include serial bus communication.
The Controller Area Network (CAN) is an ISO-defined serial communications bus for real-time applications. It was originally introduced by Bosch in the 1980s to provide a cost-effective communications bus for automotive electronics. The CAN serial bus operates at data rates of up to 1-Mb/s, has excellent error detection capabilities, and is extremely reliable. Because of these features, the CAN serial communications bus continues to be widely used throughout the automotive industry and is gaining acceptance in manufacturing, aerospace, and in many other industrial applications involving data communication between systems and sub-systems.
Typical automobile system can have several different CAN networks operating at different speeds and performing different tasks. For example, there may be a high-speed network for the power-train system and separate networks for the climate control, lights, and anti-lock brake systems.The CAN serial bus system has multimaster capabilities, meaning that all CAN nodes can transmit data, and multiple CAN nodes can request data from the bus at the same time.Unlike a traditional network, CAN does not send messages from one point to another. In a CAN network, there is no addressing of devices in the usual sense because it is the data, not the device, that is given an identifier. A priority scheme called Carrier Sense, MultipleAccess with Collision Detect (CSMA/CD) defines which device is the controller of the bus at a particular time. The identifier with the lowest numerical value has the highest priority and will therefore gain control of the bus. Any po tential bus conflicts are resolved in hardware. A message is broadcast to the network and any node that has interest in the message can pick up the data. Additionally, the CAN bus is a two-wire bus with signals called CAN_HI and CAN_LOW.