Logic Analyzer

Theory

A logic analyzer is a crucial debugging tool used for capturing and analyzing digital signals in electronic devices. It allows engineers, hackers, and pentesters to examine the state of digital circuits by providing a visual representation of signals over time.

Key concepts in the operation of a logic analyzer include:

• Data Acquisition Logic analyzers sample digital signals at high speeds, capturing data from multiple channels simultaneously. This allows users to observe the timing and behavior of different signals in real time.

• Sampling Rate The sampling rate is a critical specification of a logic analyzer, determining how accurately it can capture fast digital signals. A higher sampling rate provides more precise data, essential for troubleshooting high-speed circuits.

• Channel Count Logic analyzers can monitor multiple signals at once, typically ranging from 8 to 64 channels. More channels allow for broader monitoring of complex systems.

• Storage and Analysis After capturing data, the logic analyzer stores it in memory. The data is then analyzed using specialized software, which provides visualization tools like waveforms, timing diagrams, and protocol decoding to help users interpret the captured signals.

Usage

Logic analyzers are indispensable for a variety of tasks in digital circuit debugging and signal analysis:

• Signal Analysis They allow users to observe and troubleshoot the behavior of digital signals in microcontrollers, processors, and various digital circuits.

• Protocol Decoding Many logic analyzers can decode communication protocols (such as SPI, I2C, UART), presenting the data in a more understandable format. This makes it easier to identify communication issues or protocol errors.

• Triggering Events Logic analyzers can be set to trigger data capture when specific conditions are met. This feature is useful for isolating and capturing intermittent issues or rare events that occur in the digital circuit.

Models

• Entry-Level

  • AZDelivery Logic Analyzer ($10)

    • very cheap one from Aliexpress for example, can be difficult to setup (driver problems etc.)

    • Max sampling rate: 24MHz

• Mid-Range

  • innomaker LA1010 USB Logic Analyzer ($75)

    • pulseview compatible and also use the Kingst proprietary software

    • Max sampling rate: 100MHz

• High-End

  • Saleae Logic ($500-$1500)

    • Frequently used by myself, very reliable, analog capture capability, highly user-friendly software

    • Max sampling rate: 500MHz