Aether: Modular C/C++ Embedded Firmware Platform & Verification Suite

Engineered a production-grade, modular C/C++ embedded firmware platform for Battery Management Systems (BMS) with reusable Hardware Abstraction Layer (HAL) interfaces, SOC estimation, battery protection engine, deterministic state-machine fault handling, and CAN telemetry. Includes a Python-based firmware testing framework covering 20+ fault-injection scenarios across 10,000+ simulated execution cycles with 70%+ unit-test coverage.

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Technical Stack

• Languages: C (C99), C++, Python 3
• Hardware Interfaces (HAL): ADC, GPIO, I2C, UART, CAN 2.0B
• Firmware Architecture: Hardware Abstraction Layer (HAL), Deterministic Finite State Machine (FSM), Fault Manager, Battery Protection Engine, State of Charge (SOC) Estimator
• Testing & Verification: Native C Unit Testing, Python Ctypes Software-in-the-Loop (SIL), Fault Injection Framework (20+ scenarios), Accelerated 10K+ Cycle Simulator, Line Coverage Analysis
• Build & Environment: GCC / MinGW, Cross-Platform Python Automation, Git

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Platform Architecture

                                +----------------------------------+
                                |        System Control FSM        |
                                | (INIT, STANDBY, PRECHARGE,       |
                                |  OPERATIONAL, FAULT, RECOVERY)   |
                                +----------------+-----------------+
                                                 |
                   +-----------------------------+-----------------------------+
                   |                             |                             |
      +------------v------------+   +------------v------------+   +------------v------------+
      | Battery Protection Engine|   |   SOC Estimator Engine  |   |   CAN Telemetry Module  |
      | - Overvoltage (OVP)     |   | - Coulomb Counting (Ah) |   | - Pack Status (0x100)   |
      | - Undervoltage (UVP)    |   | - OCV Lookup Table      |   | - Cell Voltages (0x101) |
      | - Overcurrent (OCCP/ODCP)|  | - Complementary Filter  |   | - Temps & SOC (0x102)   |
      | - Temperature (OTP/UTP) |   +-------------------------+   | - Fault Mask (0x103)    |
      | - Cell Imbalance        |                                 +-------------------------+
      +------------+------------+
                   |
      +------------v------------+
      |   Fault Manager Engine  |
      | - 3-Cycle Debouncing    |
      | - Severity Evaluation   |
      | - Auto-Recovery Retries |
      +------------+------------+
                   |
  =================v========================================================================
                                 HARDWARE ABSTRACTION LAYER (HAL)
  ==========================================================================================
    +--------------+   +--------------+   +--------------+   +--------------+   +--------------+
    |  HAL ADC     |   |  HAL GPIO    |   |  HAL I2C     |   |  HAL UART    |   |  HAL CAN     |
    | Cell Voltages|   | Contactors   |   | EEPROM       |   | Serial Log   |   | Broadcast    |
    | Pack Current |   | Status LEDs  |   | Storage      |   | Debug Out    |   | Messaging    |
    | Thermistors  |   | E-Stop Pin   |   |              |   |              |   |              |
    +--------------+   +--------------+   +--------------+   +--------------+   +--------------+

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20+ Fault-Injection & Regression Scenarios

Scenario ID	Fault Condition / Test Name	Injection Method	Expected Firmware Action
01	Cell Over-Voltage (OVP)	Cell 0 > 4.25V	Latch Fault, Open Contactors, FSM -> FAULT_ACTIVE
02	Cell Under-Voltage (UVP)	Cell 0 < 2.80V	Latch Fault, Open Contactors, FSM -> FAULT_ACTIVE
03	Charge Over-Current (OCCP)	Pack Current > +40A	Latch Fault, Open Contactors, FSM -> FAULT_ACTIVE
04	Discharge Over-Current (ODCP)	Pack Current < -100A	Latch Fault, Open Contactors, FSM -> FAULT_ACTIVE
05	Charge Over-Temperature (OTP)	Temp > 45°C (Charging)	Latch Fault, Open Contactors, FSM -> FAULT_ACTIVE
06	Discharge Over-Temp (OTP)	Temp > 60°C (Discharging)	Latch Fault, Open Contactors, FSM -> FAULT_ACTIVE
07	Under-Temperature (UTP)	Temp < 0°C (Charging)	Latch Fault, Open Contactors, FSM -> FAULT_ACTIVE
08	Sensor Failure / ADC Disconnect	Sensor Valid -> False	Critical Fault, FSM -> FAULT_ACTIVE
09	Auxiliary Power Rail Low	Aux Supply < 9.0V	Latch Fault, FSM -> FAULT_ACTIVE
10	Emergency Stop (E-Stop)	Active-Low E-Stop Pin	Critical Fault, Open Contactors Instantly
11	Cell Voltage Imbalance	Delta V > 100mV	Latch Fault, FSM -> FAULT_ACTIVE
12	Transient Spike Debouncing	1-Tick Spurious Noise	Noise Filtered Out (State remains OPERATIONAL)
13	Sub-Threshold Pulse	Current @ 38A (< 40A)	Normal Operation Maintained
14	Oscillating Voltage Noise	Sine Wave Voltages	Debouncer filters noise below limit
15	I2C EEPROM Bus Timeout	Hardware Bus Hang	Communication Fault Latched
16	CAN Bus Off Recovery	CAN Transmit Error	Telemetry Engine Re-initializes
17	Contactor Stuck Open	Feedback Mismatch	Fault Active
18	Contactor Weld Detection	Feedback Mismatch	Shutdown Critical Latch
19	Recovery Retry Exhaustion	4 Sequential Faults	Permanent Shutdown Critical Latch
20	Sensor Flapping Filter	Alternating Noise	Debouncer prevents false transitions
21	Compound Multi-Fault	OVP + OTP Triggered	Both Fault Bits Latched in CAN Telemetry
22	Telemetry Transmission Rate	150ms Execution	Transmits CAN frames at 10 Hz rate

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Quick Start & Execution

1. Master Test Suite (Builds, Tests, Runs 10K Cycles, Coverage)

python tests/python/run_all_tests.py

2. Standalone C Binary Execution

python build.py
./build/bms_app.exe

3. Native C Unit Tests

./build/bms_unit_tests.exe

4. 10,000+ Cycle Stress Simulator

python tests/python/cycle_simulator.py 10000