PicoMSO

PicoMSO is an RP2040/RP2350-based mixed-signal instrument that combines a hardware-triggered logic analyzer and oscilloscope into a single firmware and libsigrok-compatible device.

It enables synchronized digital and analog capture with deterministic, hardware-level triggering using PIO and DMA.

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Features

• Mixed-signal capture (logic + analog in one session)
• Deterministic hardware triggering (PIO + DMA)
• No sample loss or software-trigger latency
• Seamless integration with libsigrok and PulseView
• Support for RP2040 and RP2350
• Prebuilt PicoMSO Desktop binaries for easy setup

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Specifications

Logic analyzer

• Channels: 16 digital
• Max sample rate: up to 200 MHz
• Capture depth:
  • RP2040: up to 30 ksamples
  • RP2350: up to 60 ksamples
• Pre-trigger buffer: up to 4 ksample
• Triggering: level and edge (hardware, real-time)

Oscilloscope

• Channels:
  • 1 × 12-bit
  • 2 × 8-bit (simultaneous)
• Max sample rate: up to 2 MS/s
• Pre-trigger: hardware circular buffer

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Hardware variants

MCU	Features	Capture depth
RP2040	Full feature set	Standard
RP2350	Same + extended RAM	Increased

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Sample-rate limits

• Analog enabled → max 2 MS/s
• Logic-only → up to 200 MHz

Requests beyond limits are rejected by the driver.

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Triggering architecture

PicoMSO implements triggering entirely in hardware using PIO + DMA:

• No firmware latency
• No missed samples
• Fully deterministic capture start

This is a key difference compared to host-triggered devices.

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Quick start

1. Flash firmware

Download from:
https://github.com/dgatf/PicoMSO/releases

Steps:

1. Hold BOOTSEL
2. Plug USB
3. Copy .uf2 to RPI-RP2
4. Done

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2. Install PicoMSO Desktop

Prebuilt desktop binaries with PicoMSO support are available here:
https://github.com/dgatf/pulseview/releases

Available packages:

• Linux: AppImage
• Windows: portable ZIP package
• macOS: DMG package

This is the recommended way to use PicoMSO.

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3. Start capturing

1. Connect your PicoMSO device via USB
2. Launch PicoMSO Desktop
3. Select the PicoMSO device from the device list
4. Configure channels, samplerate, and trigger
5. Click Run

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Notes

• Linux: if the device is not detected, install the appropriate udev rules under /etc/udev/rules.d/ and reconnect the device.
• Windows: you may need to install a WinUSB-compatible driver using Zadig.
• Prebuilt PicoMSO Desktop binaries are the recommended installation method.

Example Linux setup:

sudo cp udev/99-picomso.rules /etc/udev/rules.d/
sudo udevadm control --reload-rules
sudo udevadm trigger

PulseView

PicoMSO works directly with PulseView for interactive visualization of mixed-signal captures.

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Advanced documentation

For development details and manual host-side setup, see:

• Building guide
• Architecture
• Protocol
• Manual libsigrok setup

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Build (firmware)

git submodule update --init --recursive
cmake -S firmware/app -B build/picomso
cmake --build build/picomso

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Signal integrity note

For best results on high-speed logic signals:

• Add ~600 Ω series resistor
• Optional RC filtering for noisy environments

This significantly improves trigger stability and reduces glitches.

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Status

PicoMSO is stable and fully functional for core mixed-signal capture.

Planned improvements:

• Analog triggering
• Enhanced RP2350 support
• Extended capture configurations

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License

GPL v3 (see LICENSE file)