Mongoose

for Sean Newton

@STMicroelectronics

 by Sergey Lyubka @Cesanta, Jul 2025

Objective

  • Outline current issues with implementing network functionality from the firmware developer perspective
  • Take Threadx NetxDuo stack as an example - though other alternatives have very similar issues (Cube's LWIP, Zephyr, etc), with STM32H573I-DK board
  • Demonstrate Mongoose as a solution

Issues

  • Difficult (sometimes, very) to integrate into an existing project, or start from scratch. Only the pre-built examples work
  • Use Threadx / NetxDuo as a network stack
  • (Integrate from scratch. Use pinout)
  • Numerous NetxDuo configuration options
    • many of them make sense only for stack devs, or very experienced network devs. not for the rest
    • using constants: rigid internal structure which breaks at certain conditions
    • stack dev is unsure about values, so puts them as config params, moving the problem to firmware dev's shoulders - and they don't have a clue

Issues

  • Subtle dependencies. Example: ICache / DCache, if not enabled, then the driver crashes
  • (Open in CubeIDE, add IO retargeting, add trace)
  • Fail.
  • Ask for help... Where ? ST forum? Threadx project?
int _write(int fd, unsigned char *buf, int len) {  // Add before main()
  if (fd == 1 || fd == 2) {                        // stdout or stderr ?
    HAL_UART_Transmit(&huart1, buf, len, 999);     // Print to the UART
  }
  return len;
}

while (1) {  // Change main() loop to this:
  printf("tick: %lu\n", HAL_GetTick());
  HAL_Delay(500);
}

Issues

  • Following Nx_WebServer example
  • Low quality - overcomplicated, tons of irrelevant threads / functionality devs do not need
  • SD card reliance - bad! Can't be tried off-the-shelf. Critical UI must not be served off the file system which can fail
  • Implement a trivial web server - just serve a hello world?
  • Overcomplicated stock example
  • Clean and concise API reference - where ?

Issues

  • Longer term: developing Web UI functionality
    • No frontend expertise! Result: either badly performing UI that hurts the brand, or hiring an external team which breaks deadlines
    • Usual functionality requires a lot of extra efforts: Websocket, uploads, firmware OTA
  • TLS - could be a huge issue, especially when RAM is tight

Issues

  • Reliance on the Cube driver: very low quality, very complicated driver with a plugin system designed as a spaghetti of weak functions. 
  • Here: over 3k LoC hal_eth.c. Compare to stm32h.c
  • NetxDuo driver plugs in to HAL driver, inheriting its issues
  • Recurring "Ethernet not working" stanzas on community.st.com, reddit, and other embedded resources

Mongoose

  • Mature product:
    • open source since 2004
    • used by hundreds of enterprises, including NASA, Qualcomm, Bosch, Siemens, etc
  • Designed with the simplicity in mind. Best integration API ever, only 3 files to integrate, minimum config
  • Optional EC TLS 1.3 and TCP/IP stack with hand-written drivers
  • Excellent documentation, loads of examples and explainer videos
  • Mongoose Wizard makes Web UI and cloud functionality development effortless
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