🧪 OBC Software Test File

Estimated time to read: 6 minutes

This page documents the purpose, structure, and usage of the test file used to simulate and validate the On-Board Computer (OBC) software behavior in a controlled environment before deployment to hardware.

🧠 Purpose

The OBC software test file is written in C and provides a mock environment that allows developers to:

  • Simulate UART communication with other PIC microcontrollers (COM, RESET, MISSION)
  • Send and receive command packets
  • Validate command parsing and response generation
  • Test memory access logic and data integrity
  • Simulate reset and watchdog behavior

This file helps catch software logic issues before they affect the satellite hardware or flight model.

🗃️ File Overview

Component Description
test_obc_main.c Main test runner that initializes the OBC environment and simulates execution
mock_uart.c Simulated UART communication layer with buffers to emulate data exchange
mock_uart.h Simulated UART communication layer with buffers to emulate data exchange
mock_flash.c Emulated flash memory to verify write and read operations
mock_flash.h Emulated flash memory to verify write and read operations
test_commands.c Functions for creating and dispatching test commands
test_commands.h Functions for creating and dispatching test commands
assert_utils.c Custom assert functions for validating results
assert_utils.h Custom assert functions for validating results
test_cases.txt List of binary or ASCII commands for test input

Download Test File

To access the test file used for MAIN PIC validation, click the links above.

🔌 Interfaces Simulated

Interface Purpose Test Method
UART (to COM) Send/receive CW, payload, command packets Mocked with circular buffers and ISR simulation
UART (to RESET) Simulate watchdog and reset triggers Bitfield status and mock flags
UART (to MISSION) Exchange mission payload data Packet structures and queues
SPI (to FLASH) Write/read/verify persistent data In-memory flash map and CRC check

▶️ How to Use

  1. Compile using CCS 5.050 (or MPLAB XC32 for compatibility testing): 
    gcc -o test_runner test_obc_main.c mock_uart.c mock_flash.c test_commands.c assert_utils.c

  2. Run the executable:

    ./test_runner

  3. Analyze Output:

    • Console logs will show the command flow and state changes.
    • Errors are raised if expectations (asserts) fail.

  4. Modify Test Cases:

    • Add new scenarios in test_commands.c
    • Include payloads or flags to mimic actual satellite operations.

🧪 Example Test Flow 

// Inside test_commands.c
void test_cw_transmission() {
    send_command(COMMAND_SEND_CW);
    uint8_t* response = read_uart(COM);
    assert_string_equals("LEOPARD-CW-READY", response);
}

🧱 Build Notes

  • C99 or later
  • No hardware dependencies — all I/O is simulated
  • Can be extended for HIL (Hardware-in-the-loop) testing later
  • For integration with MPLAB, rename main to main_test() and use test harness

📎 Future Improvements

  • Add CRC verification for command packets
  • Expand flash emulation to simulate wear-out
  • Integrate with CI tools (e.g., GitHub Actions or Jenkins)