Before router

Historical development record. The current release is Leafy G.5. Use this file for context, not current ordering or wiring instructions.

Leaf Heat — Rev C

Current custom-board revision: UART programming, 41 components, four layers, 65 × 50 mm. Engineering prototype; not physically tested.

Open leaf-heat-v3.kicad_pro in KiCad 10, then open PCB Editor or Schematic Editor. Rev B is preserved in ../rev-b/.

The board receives heater commands over home Wi-Fi and communicates with the Leaf over CAN. It carries no heater current. Firmware, a verified vehicle cable, an enclosure, and prototype testing are still required.

What changed

• Replaced USB-C programming with J3, a three-pin serial programming header. Pin 1 is ground, pin 2 receives data from the adapter, and pin 3 sends data to the adapter.
• Removed USB power input, USB voltage detection, CC resistors, USB data resistors and their unused wiring/copper.
• Retained ESD protection, repurposed for the UART lines. Added two 1 kΩ series resistors and a 10 kΩ receive-line pull-up. These resistor types already exist in the BOM.
• Retained RESET and BOOT buttons, the protected vehicle power input, the CAN circuit, the antenna clearance, the ground plane and the mounting-hole positions.
• No controlled-impedance service is required for Rev C. Use the standard four-layer construction described in manufacturing notes.

There are 41 parts / 25 distinct MPNs, compared with Rev B's 47 / 29. All components are on top: 39 SMT and two through-hole connectors. The connector must be included in factory assembly.

Programming now needs a 3.3 V logic USB-to-UART adapter and a separate 12 V bench supply, connected through J1. J3 has no power pin. Follow the programming instructions; do not use a 5 V logic or RS-232 adapter.

Verification and files

Native KiCad electrical and layout checks pass with zero reported violations, unconnected items and schematic/PCB mismatches. A separate saved-file audit checks the pin map, preserved circuit connections, copper net assignments, power tolerances and BOM/placement consistency. The design review records the scope, one documented KiCad check limitation and the remaining physical tests. Passing CAD checks does not establish a working or automotive-qualified product.

• 3D preview, schematic, programming circuit
• Top copper, ground plane, power distribution, bottom copper, assembly drawing
• PCBWay BOM, JLCPCB BOM, placement coordinates, JLCPCB placement file
• Electrical check, layout check, independent audit, manufacturing audit

The native project, .kicad_dru, Leaf.kicad_sym, Leaf.pretty/ and both library tables belong together. The Gerbers in exports/fabrication/ are for Rev C only. Existing PCBWay/JLCPCB quotation requests contain Rev B, so their files and totals must not be treated as Rev C quotes.

Firmware connections

Start with CAN in standby, require a fresh authenticated heat request after every reset, and implement a bounded heating interval, explicit stop handling, bus-error handling and low-battery behavior. Wi-Fi updates and recovery/rollback must be implemented in firmware; they are not provided by this hardware revision. The earlier development-board plan uses different GPIO assignments.