Perform CAN-dbc Trigger and Decode with an Oscilloscope

Show Description

The differential Controller Area Network (CAN) bus is used extensively in all of today’s automobiles for drive-train and body control. This protocol was developed by Bosch more than 30 years ago, and it is still considered the “workhorse” serial control bus of the automobile. The CAN bus has also been heavily adopted for industrial and medical equipment control applications.

The oscilloscope is the primary measurement tool used today to test and debug the physical layer of this serial bus. Although CAN bus protocol analyzers, such as Vector’s CANanalyzer, are also commonly used for testing and debugging at a higher-abstraction application level, the advantage of an oscilloscope is that it provides you with the ability to monitor the analog quality (signal integrity) of the physical layer of the CAN bus. The electrical environment in automobiles is naturally harsh with lots of noise and often unexpected transients. The core competence of an oscilloscope is that it can capture and show you details of those infrequent automotive transients and noise that could be producing CAN bus errors.

This application note will begin by showing the difference between oscilloscope hexadecimal triggering and decode versus CAN-dbc symbolic triggering and decode of a CAN differential bus. We will then provide some background on the core element required to symbolically decode the CAN bus, which is an industry-standard .dbc file. In addition, we will provide step-by-step instructions on how to perform CAN symbolic-level triggering and decode using a Keysight Technologies, Inc. Infiniium oscilloscope. CAN-dbc symbolic triggering and decode is standard with the N8803A or N8803B CAN/LIN/FlexRay option.