# SN-L00 PCB Layout Guide

## Quick Start - Complete the Layout in KiCad

1. **Open the project**: `SN-L00.kicad_pro`
2. **Import footprints**:
   - Open PCB Editor
   - Tools → Update PCB from Schematic (F8)
   - Click "Update PCB" to import all footprints
3. **Place components**:
   - In Scripting Console (Tools → Scripting Console):
   ```python
   exec(open('scripts/place_components.py').read())
   ```
   - Or manually place using coordinates below
4. **Add mounting holes**:
   - Place `MountingHole:MountingHole_3.2mm_M3` at (14, 5) and (14, 95)
5. **Route traces**:
   - Use Freerouting: File → Export → Specctra DSN, then import routed SES
   - Or route manually with 'X' key
6. **Fill zones**:
   - Press 'B' to fill all zones
7. **Run DRC**: Inspect → Design Rules Checker
8. **Export Gerbers**: File → Fabrication Outputs → Gerbers

## Board Dimensions

| Parameter | Value | Notes |
|-----------|-------|-------|
| Width | 28.0mm | 6HP panel = 30mm, PCB 1mm clearance each side |
| Height | 100.0mm | Fits standard 3U with clearance |
| Thickness | 1.6mm | Standard PCB |
| Layers | 2 | Front + Back copper |
| Depth (mounted) | ~22mm | Skiff-friendly (<25mm) |

## Mounting Holes

| Hole | Position | Size |
|------|----------|------|
| MH1 (top) | 14.0, 5.0 | 3.2mm (M3) |
| MH2 (bottom) | 14.0, 95.0 | 3.2mm (M3) |

## Component Placement (Top to Bottom)

```
     0mm                    28mm
      │←────── 28mm ───────→│
      ┌────────────────────┐ ─┬─ 0mm
      │    ○ MH1 (M3)      │  │
      │                    │  │ 5mm
      ├────────────────────┤ ─┤
      │                    │  │
      │  ┌──────────────┐  │  │
      │  │    OLED      │  │  │ 10-25mm
      │  │   MOD2       │  │  │
      │  │  (128x32)    │  │  │
      │  └──────────────┘  │  │
      │                    │  │
      ├────────────────────┤ ─┤
      │       [BTN]        │  │ 28-35mm
      │        SW1         │  │
      ├────────────────────┤ ─┤
      │                    │  │
      │  ┌──────────────┐  │  │
      │  │  RP2040-Zero │  │  │ 38-55mm
      │  │    MOD1      │  │  │
      │  │  (18x23mm)   │  │  │
      │  └──────────────┘  │  │
      │                    │  │
      ├────────────────────┤ ─┤
      │  SMD Components    │  │
      │  U1 U2 U3          │  │ 58-75mm
      │  C1-C5 R1-R6       │  │
      │  D1-D4 D2(LED)     │  │
      ├────────────────────┤ ─┤
      │                    │  │
      │  ○ J2    ○ J3      │  │ 78-88mm
      │  TRIG   RETURN     │  │
      │                    │  │
      ├────────────────────┤ ─┤
      │  ═══════════════   │  │ 88-95mm
      │       J1           │  │
      │  (Eurorack 2x5)    │  │
      ├────────────────────┤ ─┤
      │    ○ MH2 (M3)      │  │ 95mm
      └────────────────────┘ ─┴─ 100mm
```

## Detailed Placement Coordinates

### Modules (Hand-solder)

| Ref | Component | Center X | Center Y | Rotation |
|-----|-----------|----------|----------|----------|
| MOD2 | OLED 128x32 | 14.0 | 17.5 | 0° |
| MOD1 | RP2040-Zero | 14.0 | 46.5 | 0° |

### User Interface

| Ref | Component | Center X | Center Y | Rotation |
|-----|-----------|----------|----------|----------|
| SW1 | Tactile 6x6mm | 14.0 | 31.5 | 0° |
| D2 | Power LED | 24.0 | 31.5 | 0° |
| R2 | LED resistor 1K | 24.0 | 36.0 | 90° |

### Connectors

| Ref | Component | Center X | Center Y | Rotation |
|-----|-----------|----------|----------|----------|
| J2 | Thonkiconn TRIG | 7.0 | 83.0 | 0° |
| J3 | Thonkiconn RETURN | 21.0 | 83.0 | 0° |
| J1 | 2x5 Eurorack | 14.0 | 92.0 | 0° |

### Power Section (Back side recommended)

| Ref | Component | Center X | Center Y | Rotation | Side |
|-----|-----------|----------|----------|----------|------|
| D1 | SS14 Schottky | 7.0 | 65.0 | 0° | Back |
| U1 | AMS1117-3.3 | 14.0 | 65.0 | 0° | Back |
| C1 | 10uF input | 10.0 | 60.0 | 0° | Back |
| C2 | 10uF output | 18.0 | 60.0 | 0° | Back |
| C3 | 100nF output | 21.0 | 60.0 | 0° | Back |

### Signal Conditioning

| Ref | Component | Center X | Center Y | Rotation | Side |
|-----|-----------|----------|----------|----------|------|
| U2 | 74LVC1G17 | 7.0 | 72.0 | 0° | Front |
| C4 | 100nF (U2) | 7.0 | 68.0 | 0° | Front |
| R3 | 100R trig | 7.0 | 76.0 | 90° | Front |
| U3 | MCP6001 | 21.0 | 72.0 | 0° | Front |
| C5 | 100nF (U3) | 21.0 | 68.0 | 0° | Front |
| R4 | 10K input | 21.0 | 76.0 | 90° | Front |
| R5 | 10K divider | 18.0 | 76.0 | 90° | Front |
| R6 | 22K divider | 18.0 | 72.0 | 90° | Front |
| D3 | BAT54 clamp | 24.0 | 70.0 | 90° | Front |
| D4 | BAT54 clamp | 24.0 | 74.0 | 90° | Front |

### Button

| Ref | Component | Center X | Center Y | Rotation |
|-----|-----------|----------|----------|----------|
| R1 | 10K pullup | 10.0 | 35.0 | 0° |

## Routing Guidelines

### Net Classes

| Class | Width | Clearance | Via Drill |
|-------|-------|-----------|-----------|
| Default | 0.25mm | 0.2mm | 0.3mm |
| Power | 0.5mm | 0.3mm | 0.4mm |
| Signal | 0.2mm | 0.2mm | 0.3mm |

### Power Routing

1. **+12V** path: J1 pin 4 → D1 → C1 → U1 VIN
2. **+3.3V** path: U1 VOUT → C2/C3 → distribute to all ICs
3. **GND**: Use ground pour on back layer, via stitch near decoupling caps

### Signal Routing Priority

1. I2C (SDA/SCL): Keep short, parallel, 0.5mm spacing
2. TRIG_OUT: Direct from RP2040 GP2 → U2 → R3 → J2
3. RETURN_IN: J3 → R4 → divider → U3 → RP2040 GP3
4. BTN: RP2040 GP4 → R1 → SW1 → GND

### Ground Plane

- Fill back copper with GND zone
- Via stitch every 5-10mm
- Keep clear around power input for thermal relief
- Connect GND pins of J2/J3 directly to plane

## Design Rules (PCBWay Compatible)

| Parameter | Value |
|-----------|-------|
| Min trace width | 0.15mm (0.2mm preferred) |
| Min clearance | 0.15mm (0.2mm preferred) |
| Min via drill | 0.3mm |
| Min via diameter | 0.6mm |
| Min hole size | 0.3mm |
| Min annular ring | 0.15mm |

## Silkscreen

### Front

- Component references (small, 0.8mm text)
- Jack labels: "TRIG" and "RETURN"
- "SN-L00 v0.1" at bottom
- "SubModular" at top

### Back

- "SN-L00" centered
- Pin 1 indicators for ICs
- Polarity markers for D1, power header
- "git.sub-net.at/submodular/SN-L00"

## Gerber Output

When exporting for PCBWay:

```
Required files:
- F.Cu (Front copper)
- B.Cu (Back copper)
- F.SilkS (Front silkscreen)
- B.SilkS (Back silkscreen)
- F.Mask (Front soldermask)
- B.Mask (Back soldermask)
- Edge.Cuts (Board outline)
- *.drl (Drill file)

Settings:
- Format: Gerber X2
- Drill: Excellon
- Units: mm
- Coordinate format: 4.6
```

## Assembly Notes

1. PCBWay can assemble all SMD parts on both sides
2. Hand-solder: MOD1 (RP2040-Zero), MOD2 (OLED)
3. Jacks (J2, J3) can be assembled or hand-soldered
4. Power header (J1) usually hand-soldered for alignment

## Checking Before Order

- [ ] DRC passes with no errors
- [ ] All nets connected (no airwires)
- [ ] Mounting holes align with panel
- [ ] Jacks align with panel holes
- [ ] Power header polarity marked
- [ ] Silkscreen readable and not over pads
- [ ] Ground plane connected properly