Firmware of single board OBD1 ECU

https://wiki.rusefi.com/uaEFI-Honda-OBD1

This repository is a rusEFI custom board definition: it holds only the board-specific customization on top of the rusEFI core, which lives in the ext/rusefi git submodule. This board is itself derived from the uaEFI121 board (ext/rusefi/firmware/config/boards/hellen/uaefi121/) and reuses its mega-uaefi code.

Documentation & Schematics

• Board schematics PDF is in the docs folder: docs/uaefi-Honda-OBD1-e-schematic.pdf
• docs/schematic-notes.md — text extraction of the schematic: which pages matter for firmware, full pin-mapping tables, populate-options
• docs/vato/CurrentTune.msq — a known-good reference tune
• Wiki page: https://wiki.rusefi.com/uaEFI-Honda-OBD1

Custom Board Customization

A custom board customizes rusEFI at three levels: build system (.mk/.env files), C++ code (pin defaults, validation, knock hardware), and code generation inputs (connector .yaml, TunerStudio .txt/.ini templating files).

Build system

• meta-info.env — top-level board identity: SHORT_BOARD_NAME=uaefi-obd1 (used in bundle and signature names), PROJECT_CPU=ARCH_STM32F4, USE_OPENBLT=yes (OpenBLT bootloader).
• board.mk — makefile fragment included by the rusEFI build:
  • adds board_configuration.cpp and the parent board's mega-uaefi.cpp to the build (BOARDCPPSRC)
  • adds include paths for generated/ headers and the parent uaefi121 board (BOARDINC)
  • sets the default engine type: -DDEFAULT_ENGINE_TYPE=engine_type_e::HONDA_OBD1
  • chains into the parent board's mega-uaefi.mk
• board_unit_tests.mk — adds board-specific unit tests (tests/test_example.cpp) to the rusEFI unit test suite.

C++ files

• board_configuration.cpp — the heart of board customization. Its entry point setup_custom_board_overrides() installs three hooks into the rusEFI core:

  • custom_board_DefaultConfiguration → customBoardDefaultConfiguration(): starts from the parent board defaults (setUaefiBoardDefaultConfiguration()), then assigns Honda-OBD1 pin mapping — injector pins, ICM ignition output, fuel pump, IACV, tach, VR crank/cam trigger inputs, and TPS/MAP/CLT/IAT analog channels, all via Gpio::MM100_* / MM100_IN_* symbols from hellen_mm100_meta.h.
  • custom_board_ConfigOverrides → parent board's setMegaUaefiBoardConfigOverrides().
  • custom_board_validateConfig → customBoardValidateConfig(): board-specific sanity checks; here it rejects a known-bad 24/0 toothed-wheel trigger configuration with a critical error.

  The file also defines the OUTPUTS[] table (getBoardMetaOutputs() / getBoardMetaOutputsCount() / getBoardMetaLowSideOutputsCount()) used by hardware QC / board self-test to enumerate every physical output with its connector pin.

• default_tune.cpp — boardTuneDefaults() sets tune values baked into the default calibration (e.g. displacement = 1.6 for the D16 engine).

• knock_config.h — knock sensing hardware description: which ADC (ADCD3), which pin/channel (PA3 / ADC_CHANNEL_IN3), and sample rate/time for the STM32F4.

Connector YAML (connectors/)

• connectors/honda-obd1.yaml — the machine-readable pinout definition, the single source of truth mapping physical connector pins to MCU functions. Top-level keys:

  • meta: — points at the header (config/boards/hellen_mm100_meta.h) whose symbols (e.g. MM100_INJ4, MM100_IN_CLT_ANALOG) are referenced by pin entries.
  • pins: — one entry per physical pin across the Honda OBD1 A/B/D ECU connectors plus the board's own J1–J5 adapter connectors and the C AUX plug. Per-pin fields:
    • pin: — connector pin name (e.g. A7, B15, J4_8)
    • class: — role: outputs, analog_inputs, event_inputs, switch_inputs (a list plus id: list when one pin serves two roles)
    • meta: — the MCU signal symbol from the meta header; generates the PIN_xxx defines
    • ts_name: — pin display name in TunerStudio drop-downs
    • function:, type: (inj/ign/ls/hs/av/at/gnd/5v/12v/can/hall/etb), color: — documentation for humans and the interactive pinout
  • info: — interactive pinout metadata: board title, wiki URL, connector photo (76pin-178780.jpg) and x/y coordinates of every pin on that image.

  From this YAML, rusEFI automation (PinoutLogic.java) generates the files that sit next to it: generated_board_pin_names.h, generated_outputs.h, generated_ts_name_by_pin.cpp. Never edit the generated_* files manually — edit the YAML and regenerate.

• connectors/readme.md — how to activate custom pin naming for the interactive pinout.

TunerStudio .ini templating & config generation

• prepend.txt — #define flags prepended during .ini generation to tailor the TunerStudio dialogs to this board: hides irrelevant UI (ETB pins, bank-2 cams, cylinders 5–12, rotary/HD options...), shows VR threshold settings, and overrides table sizes (IGN_TRIM_SIZE 8).
• extra.txt — board-specific data points added to the configuration definition (struct_no_prefix extra_s — currently empty).
• board_config.txt — board-specific calibrations hook (see comments inside).
• board_indicators.ini — board-specific TunerStudio indicators (see gen_config_common.sh).
• generated/ — output of config generation: TunerStudio .ini, console live-data files, simulator tunes, canned tunes. Auto-generated; normally refreshed by GitHub Actions or manual-generate-meta-data.sh.

Build & maintenance scripts

• compile_firmware.sh — build the firmware locally (wraps ext/rusefi/firmware/bin/compile.sh with this board's meta-info.env).
• _compile_bundle.sh / _compile_bootloader.sh / _compile_simulator.sh / _compile_unit_tests.sh — build the full bundle, OpenBLT bootloader, simulator, and run board unit tests respectively.
• manual-generate-meta-data.sh — run config/code generation locally (GitHub Actions is the recommended path).
• bin/update-rusefi.sh — reset and re-init the ext/rusefi submodule to a clean state.
• bin/git_clean.sh — deep-clean repo and submodule.
• extra_files_to_copy_on_image/ — extra files (Discord/nightly bundle links) copied into the firmware bundle image.

Tests

• tests/test_example.cpp — board-specific GoogleTest cases, wired in via board_unit_tests.mk and run by _compile_unit_tests.sh.