The ability to analyze with precision over I2C and SPI is paramount when it comes to systems and hardware-level debugging. Embedded Systems Engineers have found two widely used solutions and techniques when working with these common serial buses:

1.     Oscilloscopes

2.     Protocol Analyzers

Each solution can be extremely effective depending on the use case and understanding their key differences is vital to selecting the optimal approach.

What is the Difference Between a Protocol Analyzer and an Oscilloscope? 

At a high level, the key differences are: 

• Oscilloscope
  • Provides physical wave form
  • Snapshot of waveform
  • Options for protocol decoding

• Protocol Analyzers
  • Provides protocol data (hex)
  • Large buffer of data streams
  • No waveform, protocol only

Fundamentally, each method provides different ways to analyze embedded systems. Oscilloscopes are very useful for debugging electrical issues, but the captured data is at a very low level. A key function however is that they perform a quick diagnostic with visual data representing elements such as jitter, noise, and signal to noise ratio (SNR). 

As opposed to oscilloscopes, protocol analyzers allow engineers to effectively debug at a higher level. Protocol analyzers allow users to view the data in the form of decoded, easy to understand packets and not just individual bit streams. They also allow engineers to stream data packets and low-level bus events for further debugging.

 Data Center Software I2C Capture

While oscilloscopes are useful in debugging embedded applications through physical waveform analysis, it is evident that protocol analyzers have additional significant benefits.

What Are the Benefits of Using a Protocol Analyzer over an Oscilloscope? 

Portable

Protocol Analyzers are typically handheld and extremely practical within any lab or even home-based testing environment as opposed to larger oscilloscopes that may not be ideal for certain applications due to their size.

Plug and Play

In addition to taking less space than oscilloscopes, protocol analyzers are also easy to set up given their plug and play configuration with a host PC and their ability to operate within multiple OS environments.

Real-Time Data and Detailed Analysis

Protocol analyzers with real time data capture capabilities allow engineers to quickly monitor and display real-time packet level data over the I2C or SPI bus, which more easily pinpoints valuable data transmissions and potential errors, thus leading to more thorough analysis and debugging. Pertinent data points that can often be examined using protocol analyzers include:

• Transaction Timestamp
• Transaction Duration
• Error Message
• Start or Stop Command
• Device Address
• Decoded Data

Cost Differences

Typical oscilloscopes can be costly and range in the low to high five figures while most protocol analyzers remain at a fraction of the cost.

In summary, using either an oscilloscope or a protocol analyzer has its key advantages depending on the level of usage, however protocol analyzers have become a method of choice for the Embedded System Engineer.  

How Does the Beagle I2C/SPI Protocol Analyzer Compare to Others? 

Choosing the right solution is an important process, and tools like Total Phase’s industry-leading Beagle I2C/SPI Protocol Analyzer have emerged to give engineers the capabilities to more easily, quickly, and cost-effectively debug and develop embedded applications with serial buses. 

Specifically, the Beagle I2C/SPI Protocol Analyzer is a portable device that allows engineers to quickly and easily analyze and debug I2C and SPI traffic in real-time, a capability specific to Total Phase analyzers. While many protocol analyzers do work in different OS environments, the Beagle I2C/SPI Protocol Analyzer offers cross-platform support and can operate in the most widely used environments, including Windows, Mac OS, and Linux. Our analyzers provide visibility into various data transactions and provide the option to filter data as needed. Additionally, our Beagle analyzer is one of the most affordable protocol sniffing solutions in the embedded space, making it a go-to tool for many engineers. 

For further information on how this device can support your debugging efforts, please visit the Beagle I2C/SPI Protocol Analyzer product page.