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03 — First Build & Run

This is the final step. You should have your first firmware running on the board — with an LED blinking — in about 20 minutes. This guide assumes you have already completed 01 Hardware Setup and 02 Software Setup.

The C code you write is just text. The processor inside the board cannot read text — it only executes machine code. That means every change requires two steps:

  • Build — compile your C code into machine code (.elf)
  • Flash — write that machine code into the board's memory

You will repeat these two steps dozens or hundreds of times as you develop.

Build Outputs

STM32CubeIDE generates these automatically:

  • Debug/Extension_Module.elf — debug build with symbol information (used during development)
  • Debug/Extension_Module.bin / .hex — binary files for production deployment
  • Console log — compile errors, warnings, and memory usage summary

Steps

1. Import the Project

File → Import... → General → Existing Projects into Workspace → Next

Click Browse... and select the extracted folder itself: - Recommended path: C:\dev\Extension_Module\ (the .project file is at the folder root)

The SDK ZIP ships as a flat archive per revision (Rev1.1.zip / Rev2.0.zip), so extracting it places your revision's SDK directly at the ZIP root. There is no inner revision subfolder to navigate into.

When Extension_Module appears in the Projects: list, click Finish.

✅ Extension_Module now appears in the Project Explorer panel on the left.

2. Apply Example Code (Optional)

The default project builds and boots as-is — LED 1 will blink in a heartbeat pattern. To try a specific example:

  • Option A (recommended) — Copy the entire contents of an example file such as Examples/00_Quick_Start/quick_start.c and paste it into XM_Apps/Control_Task/control_task.c.
  • Option B — Move the example .c file into the Control_Task folder and delete the existing control_task.c.

3. Build

Go to Project → Build All (shortcut: Ctrl + B), or click the hammer icon in the toolbar.

The Console panel streams the compile log in real time. The first build takes roughly 5 minutes because it compiles several hundred files.

✅ A successful build ends with: 

   text    data     bss     dec     hex filename
 XXXXXX   YYYYY   ZZZZZ  AAAAAA  BBBBBB Extension_Module.elf

13:23:45 Build Finished. 0 errors, N warnings. (took XmYs)
"0 errors" is what matters. Warnings can be ignored.

4. Flash & Run

Debug mode (recommended): 1. Click the bug icon (Debug) in the toolbar. 2. If ST-Link is detected, STM32CubeIDE automatically flashes the firmware and pauses execution. 3. STM32CubeIDE switches to the Debug perspective. 4. Press Resume (F8) to start running code on the board.

Normal run mode: 1. Click the play icon (Run) in the toolbar. 2. After flashing completes, the board starts running automatically.

5. Verify Operation

If LED 1 on the XM10 board blinks in a heartbeat pattern at a 1-second interval, the firmware is running correctly.

If you applied example code, follow the "Experiment" steps in that example's README (e.g., Ex.00: press BTN 1 and check the USB message).

Common Issues

Build

  • fatal error: 'xxx.h' file not found — An include path is missing. Check Project Properties → C/C++ Build → Settings.
  • undefined reference to 'xxx' — A library (.a) file is missing. The SDK folder may be corrupted — go back to step 02 and re-download and re-extract the ZIP.
  • region 'RAM' overflowed by N bytes — Your code exceeds the memory limit. Start by reducing the size of large arrays or structs.
  • Build is very slow — Your antivirus software may be continuously scanning temporary build files. Add the STM32CubeIDE workspace folder to the antivirus exclusion list.
  • 1 errors — Copy the full red error message from the top of the Console and ask an AI assistant about it.

Flash

  • "No ST-Link detected" — Check your USB cable and port. Avoid USB hubs; plug directly into a rear port on your PC.
  • "Target no device found" — The board may not be powered, or the SWD 4-pin connector is misaligned. Check the pin 1 marker.
  • "Old firmware on ST-Link, please update" — STM32CubeIDE is asking you to update the ST-Link firmware. Click Yes.
  • "Connection error" during flash — In Debug Configurations → Debugger tab, change Reset Behaviour to Connect under reset.

Runtime

  • LED 1 does not turn on — Flash may have failed, or the board halted after booting. Press the Reset button on the board once.
  • LED blinks very rapidly (error signal) — The firmware entered a fault handler. In the Debug perspective, click Suspend and check which function the PC register points to.
  • No USB serial messages appear — The USB-CDC serial port can only be opened by one application at a time. Close any other clients such as PhAI Studio and try again.

What's Next

Your development environment is ready. Time to start writing code.

  • First example → Ex.00 Quick Start (verifies board operation)
  • Learning path → tutorials/README.md (48 examples + recommended order)
  • Suggested starting sequence: Ex.00 → Ex.01 → Ex.02 → Ex.03 (buttons + LEDs, ⭐~⭐⭐)