When debugging serial links in embedded designs such as I-squared C, SPI, CAN, LIN, and Flexray, MSOs are an effective tools for:

- Seeing what’s happening on the serial link;
- Looking at the relationship between serial links and other system activity; and
- Quickly tracking down protocol violation errors.

While MSOs let you acquire serial signals with either digital or analog channels, it’s often convenient to use the digital channels for triggering and viewing bus activity…leaving the analog channels available to look at other system events

In this example we’re comparing the capabilities of Agilent's MSO6054A with the Tektronix MSO4054. We've connected each scope to the same I-squared-C clock and data signals on their digital channels.

Decoding a serial bus on the Agilent MSO is fast uses an internal FPGA to produce real-time protocol decode—without decreasing the scope’s fast update rate.

In contrast, decoding the same bus on the Tek MSO significantly slows the scope’s responsiveness. Waveforms and serial decode are updated sequentially at different times instead of simultaneously—in this case about 4 seconds between acquisitions.

Any event that occurs during that processing dead time on the Tek, will be missed.

Make sure your next MSO offers the fastest way to debug your serial buses.