florian.berthold
cd337b8718
- autoroute.sh: Downloads and runs Freerouting in batch mode - Updated README with complete PCB layout workflow - Script handles DSN→SES conversion automatically Usage: Export DSN from KiCad, run ./autoroute.sh, import SES
137 lines
3.6 KiB
Markdown
137 lines
3.6 KiB
Markdown
# SN-L00 Latency Tester
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Eurorack module for measuring round-trip latency in audio/CV signal chains.
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**Organization**: [SubModular](https://git.sub-net.at/submodular) / Sub-Net e.U.
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## Features
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- Measures latency from 0.01ms to 999ms
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- 128×32 OLED display showing milliseconds
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- Three modes: Single shot, Continuous, Statistics
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- Skiff-friendly depth (<25mm)
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- USB serial output for logging
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## Specifications
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| Parameter | Value |
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|-----------|-------|
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| Width | 6 HP (30mm) |
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| Depth | <25mm |
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| Power +12V | ~25mA |
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| Power -12V | 0mA |
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| Resolution | 0.01ms |
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| Output | 0-3.3V trigger |
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| Input | 0-10V tolerant |
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## Project Structure
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```
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SN-L00/
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├── hardware/
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│ ├── BOM.md # Bill of materials with LCSC part numbers
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│ ├── kicad/ # KiCad schematic and PCB
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│ │ ├── SN-L00.kicad_pro
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│ │ ├── SN-L00.kicad_sch
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│ │ ├── SN-L00.kicad_pcb
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│ │ ├── README.md # ASCII schematic reference
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│ │ └── PCB_LAYOUT.md # Placement guide
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│ └── panel/
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│ ├── PANEL_SPEC.md # Dimensions and specifications
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│ └── SN-L00_panel.svg # Panel design
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├── firmware/
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│ ├── CMakeLists.txt # Pico SDK build
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│ ├── README.md # Build instructions
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│ ├── include/ # Header files
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│ └── src/ # Source files
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└── docs/
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└── DESIGN.md # Technical design document
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```
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## Hardware
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### Components
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| Part | Description |
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|------|-------------|
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| MCU | RP2040-Zero (Waveshare) |
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| Display | 0.91" OLED 128×32 I2C |
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| Output buffer | 74LVC1G17 Schmitt trigger |
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| Input buffer | MCP6001 op-amp |
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| Regulator | AMS1117-3.3 LDO |
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Full BOM with LCSC part numbers in [hardware/BOM.md](hardware/BOM.md).
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### PCB Layout (KiCad 8)
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1. Open `hardware/kicad/SN-L00.kicad_pro`
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2. Update PCB from schematic: **Tools → Update PCB from Schematic** (F8)
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3. Place components using the script:
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```python
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# In KiCad Scripting Console (Tools → Scripting Console)
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exec(open('scripts/place_components.py').read())
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```
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4. Autoroute using Freerouting:
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```bash
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# Export DSN from KiCad: File → Export → Specctra DSN
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./hardware/kicad/scripts/autoroute.sh
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# Import SES in KiCad: File → Import → Specctra Session
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```
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5. Fill zones: Press **B**
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6. Run DRC: **Inspect → Design Rules Checker**
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7. Export Gerbers: **File → Fabrication Outputs → Gerbers**
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### Manufacturing
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- PCB: 2-layer, 28×100mm
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- Assembly: PCBWay or similar (SMD parts)
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- Hand-solder: RP2040-Zero module, OLED module
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- Panel: Aluminum or PCB (6HP)
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## Firmware
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Built with Raspberry Pi Pico SDK.
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```bash
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export PICO_SDK_PATH=/path/to/pico-sdk
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cd firmware
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mkdir build && cd build
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cmake .. && make
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```
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Flash `sn_l00.uf2` via USB bootloader.
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See [firmware/README.md](firmware/README.md) for details.
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## Usage
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1. Connect **TRIG OUT** to your signal chain input
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2. Connect your signal chain output to **RETURN IN**
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3. Press button to measure latency
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4. Long press to toggle continuous mode
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### Modes
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- **SINGLE**: Press to measure once
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- **CONT**: Auto-measures every 500ms, shows live reading
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- **STATS**: Shows min/max/average after continuous mode
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## Typical Latency Values
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| Source | Expected Latency |
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|--------|------------------|
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| Analog modules | <0.1ms |
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| Digital Eurorack (DSP) | 1-5ms |
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| Audio interface round-trip | 3-20ms |
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| DAW + plugins | 5-50ms+ |
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## License
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TBD
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## Links
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- Repository: https://git.sub-net.at/submodular/SN-L00
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- Organization: https://git.sub-net.at/submodular
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- Parent: [Sub-Net e.U.](https://sub-net.at)
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