Corne chocolate

Corne Chocolate Wireless

A modern, low-profile split ergonomic keyboard based on the Corne (crkbd) Chocolate v2.1 footprint. Designed for completely wireless operation with nice!nano v2, native 5-pin nice!view (Sharp Memory LCD) support, onboard power management, and RGB backlighting.

Key Features

• Low-Profile Choc v1: Kailh Choc PG1350 switches with hotswap sockets.
• Native nice!view Header: 5-pin pinout tailored specifically for nice!view and Sharp Memory LCD modules ([CS, MOSI, SCK, VCC, GND]) without adapter boards or bodge wires.
• Dedicated Power Control: Onboard slide power switch (PCM12) and 2-pin JST-PH 2.0mm LiPo battery connector routing power directly to the controller's RAW pin.
• RGB Matrix & Underglow: 27× SK6812MINI LEDs per side (6 underglow + 21 per-key).
  • WS2812 data line routed to Pin 2 (P0.08 / D0) to dedicate Pin 1 (P0.06 / D1) to the display Chip Select (CS).
• Reversible PCB: A single reversible PCB design is flipped for either the left or right hand.
• ZMK Firmware Ready: Complete ZMK configuration, keymap, and GitHub Actions build workflow included out of the box.

Hardware Specifications & Pinout

Microcontroller (nice!nano v2 / nRF52840)

5-Pin Display Connector Pinout

Viewed from the front (component side) with header pins at the bottom:

Pin:    [ 1 ]      [ 2 ]      [ 3 ]      [ 4 ]      [ 5 ]
Signal:  CS        MOSI       SCK        VCC        GND
        (P0.06)    (P0.17)    (P0.20)   (3.3V)

Assembly & Solder Jumpers

Because the PCB is reversible, you bridge the 5 solder jumpers on the top (active) side of each half to route the display signals:

• Left Hand (Top / Front side facing up): Solder jumpers JP1 through JP5 on the front layer (F.Cu).

  • JP5 $\rightarrow$ Pin 1 (CS)
  • JP4 $\rightarrow$ Pin 2 (MOSI / SDA)
  • JP3 $\rightarrow$ Pin 3 (SCK / SCL)
  • JP2 $\rightarrow$ Pin 4 (VCC)
  • JP1 $\rightarrow$ Pin 5 (GND)

• Right Hand (Bottom / Back side facing up): Solder jumpers JP6 through JP10 on the back layer (B.Cu).

  • JP6 $\rightarrow$ Pin 1 (CS)
  • JP7 $\rightarrow$ Pin 2 (MOSI / SDA)
  • JP8 $\rightarrow$ Pin 3 (SCK / SCL)
  • JP9 $\rightarrow$ Pin 4 (VCC)
  • JP10 $\rightarrow$ Pin 5 (GND)

[!TIP] Only solder the jumpers on the top side of each half. Leave the jumpers on the underside unbridged.

Fabrication & Ordering

Ready-to-manufacture files are located in hardware/production/:

Recommended Fab Settings (JLCPCB)

• Base Material: FR-4 (1.6mm thickness or 1.2mm for ultra-low profile)
• Layers: 2 layers
• Surface Finish: ENIG (recommended for hotswap durability) or HASL Lead-Free
• Silkscreen: Black PCB with white silkscreen (or standard preferences)
• Castellated Holes: No

Firmware (ZMK)

The repository includes a battle-tested ZMK setup under firmware/:

• Custom SPI Pinctrl: Configures P0.08 for the WS2812 LED chain, preserving P0.06 for display CS.
• Sleep & Power Management: Deep sleep timeout set to 30 minutes with soft-off support.
• ZMK Studio: Enabled for real-time keymap remapping without reflashing.

Building Firmware

Build using the included GitHub Actions workflow or locally with the ZMK toolchain:

west build -b nice_nano//zmk -d build/left -- -DSHIELD="corne_left nice_view_adapter nice_epaper"
west build -b nice_nano//zmk -d build/right -- -DSHIELD="corne_right nice_view_adapter nice_epaper"

Repository Layout

.
├── hardware/                  # KiCad 9 PCB and Schematic source files
│   ├── corne-chocolate.kicad_pro
│   ├── corne-chocolate.kicad_sch
│   ├── corne-chocolate.kicad_pcb
│   ├── corne-chocolate.step
│   ├── kbd/                   # KiCad symbol & footprint libraries
│   └── production/            # Gerbers, Drill, BOM, and CPL files
└── firmware/                  # ZMK configuration & build recipes
    ├── config/                # corne.keymap and corne.conf
    └── build.yaml             # GitHub Actions matrix configuration