Build Your Own 100Msps Logic Analyzer with Raspberry Pi Pico

Unlock Digital Debugging with the Open-Source Pico-Based Logic Analyzer

Debugging digital circuits and embedded systems often requires specialized tools, and a logic analyzer is indispensable for observing digital signal behavior. While professional-grade logic analyzers can be costly, the open-source LogicAnalyzer project offers a powerful, affordable alternative built around the versatile Raspberry Pi Pico. This project provides everything you need to construct a 24-channel, 100Msps logic analyzer capable of capturing up to 32k samples deep, complete with advanced triggering capabilities and a sophisticated multiplatform software application.

What is LogicAnalyzer?

LogicAnalyzer leverages the Raspberry Pi Pico's programmable I/O (PIO) state machines to achieve high-speed data capture. Unlike traditional microcontrollers that struggle to keep up with high-frequency signal analysis due to CPU overhead, the Pico's PIO units are purpose-built for efficient, single-cycle I/O operations. This allows the LogicAnalyzer to implement sophisticated triggering mechanisms—including edge, fast pattern, and complex pattern triggers—at rates up to 100Msps.

The project encompasses: * Hardware Designs: Schematics and PCB layouts for the core analyzer unit and an optional level shifter board (essential for working with 5V signals, as the Pico is 3.3V native). The designs are optimized for precision, ensuring minimal signal degradation even at high speeds. * Firmware: Optimized firmware for the Raspberry Pi Pico, available as easy-to-flash UF2 files. The firmware handles high-speed data acquisition and advanced triggering. * Software Application: A robust, multiplatform desktop application built with AvaloniaUI, compatible with Windows, Linux, and macOS. This user-friendly interface allows for detailed visualization of captured data, channel naming, region highlighting, and integration with protocol analyzers (SPI, I2C, Serial, etc.).

Key Features and Capabilities

• High Performance: 24 channels with a sampling rate of 100Msps, crucial for analyzing fast digital buses.
• Deep Memory: Captures up to 32,767 samples, with ongoing development to increase this substantially (up to 131,071 samples in 8-channel mode and even 380k+ samples with Pico 2 support).
• Advanced Triggering: Supports edge-triggered, fast pattern-triggered (up to 5 channels), and complex pattern-triggered (up to 16 channels) captures, enabling precise isolation of specific events.
• Multiplatform Software: A dedicated graphical user interface (GUI) application offers an intuitive experience for data visualization, analysis, and protocol decoding. It supports exporting captures to standard formats like Sigrok/PulseView.
• WiFi Support (Pico W): Future updates are set to integrate full WiFi capabilities via the Raspberry Pi Pico W, allowing for wireless data transfer and even battery-powered remote operation—a game-changer for in-situ debugging of difficult-to-access systems.
• Daisy Chaining: A significant enhancement in Release 4.0 allows for daisy-chaining multiple analyzer boards, expanding the channel count to a massive 120 channels across five chained devices.
• Protocol Analyzers: Built-in support for common protocols like SPI, I2C, and RS-232, with an easy-to-use plugin system for developing custom decoders.
• Community and Support: The project is actively maintained, with a responsive developer and an engaged community contributing to its evolution and providing support.

The Power of PIO

The secret behind LogicAnalyzer's impressive performance lies in the Raspberry Pi Pico's PIO units. These dedicated hardware blocks can run small, deterministic programs at high speeds, independent of the main CPU. This parallel processing capability is what enables the LogicAnalyzer to simultaneously capture data and detect complex trigger conditions without missing a beat, a feat that would be impossible with traditional CPU-driven GPIO sampling.

Get Started with Your Own Logic Analyzer

Whether you're a seasoned electronics enthusiast, an embedded systems engineer, or a student eager to learn about digital signals, the LogicAnalyzer project offers a fantastic opportunity to build a professional-grade tool at a fraction of the cost. The comprehensive documentation on the project's GitHub page, including schematics, firmware, and software build instructions, makes it accessible for anyone with basic electronics and programming knowledge.

Dive into the world of digital debugging today by exploring the LogicAnalyzer GitHub repository and contribute to this exciting open-source endeavor!