Serial buses such as I2C, SPI, RS232/422/UART, CAN, LIN, FlexRay, I2S, MIL-STD 1553, ARINC 429, USB 2.0/3.0 etc., are pervasive in many of today’s digital and mixed-signal designs. Verifying proper bus communication along with analog signal quality measurements requires using an oscilloscope. Many engineers and technicians verify serial bus communication with an oscilloscope using a technique known as “visual bit counting”. But this manual method of decoding a serial bus can be time consuming and prone to errors. However, many of today’s DSOs and MSOs have optional built-in serial bus protocol decode and triggering capabilities. If your designs include serial bus technology, then selecting a scope that can decode and trigger on these buses can be a significant time-saver to help you debug your systems faster.
Most scopes on the market today that have serial bus analysis capabilities utilize softwarebased decoding techniques. With software-based decoding, waveform and decode-update rates tend to be slow (sometimes seconds per update). This is especially true when using scopes with deep memory, which is often required to capture multiple packetized serial bus signals. And when analyzing multiple serial buses simultaneously, software techniques can make protocol-specific decode update rates even slower.
Keysight’s InfiniiVision and Infiniium Series oscilloscopes utilize hardware-based decoding to provide virtual real-time updates. Faster decoding with hardware-based technology enhances scope usability, and more importantly, the probability of capturing infrequent serial communication errors.