CI

An embedded C project demonstrating a two-node Body Control Module (BCM) system communicating over CAN FD. One node reads physical switches and acts as the bus master; the other drives lighting outputs based on received commands.

Lighting output LEDs (HEAD, PARK, LEFT, RIGHT, HAZARD, HB_LED) are mapped via lighting_node/Core/Inc/main.h and driven from io_lighting_outputs.c.

• CAN FD with BRS — arbitration phase at 500 kbps, data phase at 2 Mbps; TDC (Transmitter Delay Compensation) auto-enabled via MCP2517FD.
• Heartbeat supervision — BCM increments a counter in every 100 ms command frame; Lighting Node detects a fresh counter value and resets a 350 ms watchdog. Timeout triggers fail-safe mode automatically.
• CRC-8/SAE-J1850 frame integrity — bytes [0..14] of every 16-byte CAN FD frame are protected by CRC-8/SAE-J1850 (polynomial 0x1D, init 0xFF, final XOR 0xFF). The CRC byte is placed at byte [15]; receivers reject any frame whose computed CRC does not match the received byte.
• Lamp command arbitration — hazard overrides individual indicators; left and right indicators are mutually exclusive; all are encoded as bit-flags in a single command_bits byte.
• UART diagnostics — svc_log service formats timestamped trace lines (TX/RX frames + application events) over USART2 at boot and every cycle.
• Link LED feedback — BCM master REAR_LINK_LED: off = status timeout, solid = lighting node in fail-safe, fast blink (120 ms) = healthy link.

Two-Node-BCM-Control-System/
├── bcm_master/ STM32CubeIDE project — BCM Master Node
│ └── Core/
│ ├── Inc/
│ │ ├── app_bcm.h Application layer public API + diagnostics struct
│ │ ├── can_test.h CAN test constants (ID, DLC)
│ │ ├── canfd_spi.h SPI transport primitives for MCP2517FD
│ │ ├── com_lighting_if.h Encode/decode + checksum API
│ │ ├── io_bcm_inputs.h Switch debounce + latch state
│ │ ├── lighting_messages.h Shared frame layouts and bit-flag defines
│ │ ├── main.h HAL pin definitions (CubeMX-generated)
│ │ ├── mcp2517fd_can.h MCP2517FD register driver API
│ │ └── svc_log.h UART log service
│ └── Src/
│ ├── app_bcm.c Main run-cycle: inputs → CAN TX → RX poll → LED
│ ├── canfd_spi.c SPI reset, read/write word/bytes
│ ├── com_lighting_if.c Checksum calculation, frame encode/decode
│ ├── io_bcm_inputs.c 30 ms debounce, toggle-latch arbitration
│ ├── main.c HAL init + superloop calling AppBcm_*
│ ├── mcp2517fd_can.c Mode control, bit-timing, FIFO config, TX/RX
│ └── svc_log.c Buffered UART formatter (hex, decimal, trace)
├── lighting_node/ STM32CubeIDE project — Lighting Node
│ └── Core/
│ ├── Inc/
│ │ ├── app_lighting.h Application layer public API + diagnostics struct
│ │ ├── io_lighting_outputs.h Output state and apply functions
│ │ └── main.h HAL pin definitions
│ └── Src/
│ ├── app_lighting.c Main run-cycle: RX poll → outputs → TX status
│ ├── io_lighting_outputs.c Fail-safe, command apply, GPIO write
│ ├── main.c HAL init + superloop calling AppLighting_*
│ └── (shared drivers) canfd_spi.c, mcp2517fd_can.c, com_lighting_if.c,
│ svc_log.c — identical copies in each project
└── tests/ Host-side unit test stubs (no MCU required)
 ├── test_heartbeat_timeout.c
 ├── test_checksum_validation.c
 ├── test_lamp_arbitration.c
 └── test_runner.c

• STM32CubeIDE 1.14 or later
• ST-LINK/V2 or on-board ST-LINK (Nucleo-L152RE)
• Two Nucleo-L152RE boards with Longan CAN FD shields attached

1. Open STM32CubeIDE and import both projects:

   • File → Import → Existing Projects into Workspace
   • Select bcm_master/ and lighting_node/ separately.

2. Build each project:

   • Right-click project → Build Project (or Ctrl+B).
   • Ensure zero errors in the Console view.

3. Flash BCM Master:

   • Connect the first Nucleo board via USB.
   • Right-click bcm_master → Run As → STM32 Cortex-M C/C++ Application.

4. Flash Lighting Node:

   • Connect the second Nucleo board via USB.
   • Right-click lighting_node → Run As → STM32 Cortex-M C/C++ Application.

5. Connect the two CAN FD boards (CANH–CANH, CANL–CANL, GND–GND) and ensure at least one 120 Ω termination resistor is present on the bus.

6. Open a serial terminal (115 200 8N1) on each board's USB-UART port to watch the svc_log trace output.

cd tests
gcc -I./stubs \
 -I../bcm_master/Core/Inc \
 -I../lighting_node/Core/Inc \
 test_runner.c \
 test_heartbeat_timeout.c \
 test_checksum_validation.c \
 test_lamp_arbitration.c \
 ../bcm_master/Core/Src/com_lighting_if.c \
 ../bcm_master/Core/Src/io_bcm_inputs.c \
 ../lighting_node/Core/Src/io_lighting_outputs.c \
 -o run_tests && ./run_tests

Expected output: Results: 66 passed, 0 failed

The tests/stubs/ directory provides minimal HAL type definitions (stm32l1xx_hal.h, main.h, gpio.h). All HAL function calls (HAL_GetTick, HAL_GPIO_ReadPin, HAL_GPIO_WritePin, HAL_Delay) are implemented as lightweight shims in test_runner.c.