ARM Embedded Tutorial - Entry FPC and STM32

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Introduction to STM32 and FPC

This tutorial was tested using 64 bit Linux Mint.

Driver for ST-LINK V2


Download the package as a zip with clone or download from

Follow the instructions at

The following packages must be installed:

  • CMake (minimum v2.8.7)
  • C compiler (gcc, clang, mingw)
  • Libusb 1.0 (minimum v1.0.9)
 sudo apt-get install cmake
 sudo apt-get install gcc
 sudo apt-get install
 // sudo apt-get install libusb-dev // ???

Compile and install stlink:

 $ make release
 $ make debug

 $ mkdir build # may already exist.
 $ cd build
 $ cmake -DCMAKE_BUILD_TYPE = Debug ..
 $ make

To install in your home directory:

 $ cd build/release
 $ make install DESTDIR=$HOME

To install for all users:

 $ cd build/release
 $ sudo make install

Reboot or:

 $ sudo udevadm control --reload-rules
 $ sudo udevadm trigger

Then there should be a device file /dev/stlinkv2_3 or similar.

Run the following as a test:


This should produce several lines of information, including how much SRAM the controller has. You can then cancel it with Ctrl+C.

If st-util aborts with the following error:

 st-util: error while loading shared libraries: cannot open shared object file: No such file or directory

This is probably the problem: so run the following:

 $ sudo ldconfig

Windows/macOS (not tested) 

Hardware connections

Connect the ST-LINK V2 to the STM32F103C as follows:

ST LINK V2 -> STM32F103C
3.3V -> 3.3V

Set up Arduino IDE (optimal)

This is not absolutely necessary, but it has the advantage that you can look up how problems have been solved there, eg I²C access.

Note the following page (does not work with Sloeber (Eclipse for Arduino)) 

JSON link: 

The following JSON also works with Sloeber. Insert this JSON link in the Arduino IDE under File > Preferences: (Version 2018.4.2 has been tested.) 

It is also best to activate the detailed output for compilation and upload. Then you can see any error uploading. Attention: Uploading is completed with the green bar which is displayed, even if an error occurred in the detailed report.

Install the following in the board management:

 stm32duino/STM32F1xx ... 

Configure the board under Tools:

  • Board Generic STM32F103 series
  • Serial Interface No Serial
  • Upload method STLINK

First start

Upload the Arduino blink sketch, then the LED PC13 should blink. Possibly. Set port to PC13.

Build Lazarus with FPCUPdeluxe

Build trunk

Download FPCUPdeluxe-[OS] from It is best to copy the download of FPCUPdeluxe into a new empty folder and then start the copied file in the file manager with a double click. Linux asks if the file should be made executable, answer yes. The FPCUPdeluxe GUI should then start.

  • Set the top left list boxes FPC version and Lazarus version to trunk or embedded which are both in the Basic tab.
  • Build the Lazarus base trunk/embedded version with Install/update FPC+Laz.

If everything goes through without errors you get the current trunk from FPC and Lazarus. Normal desktop applications can now be created with this. There should be an icon for Lazarus_fpcupdeluxe on the Desktop.

Light bulb  Note: Note: SVN repositories may experience difficulties. If so, don't give up, just try again later ;-) What also helps, run FPCUPdeluxe twice in a row. An out of date FPCUPdeluxe can also cause difficulties. If something doesn't work, you can ask in the Lazarus forum, the author is very helpful.

Build ARM cross compiler

Press the Setup+ button in the Cross tab to open a dialog with further options. Set the following there:

  • "Use jobs for GNU make": Remove hooks.
  • CPU: arm
  • OS: embedded
  • Cross SubArch Overide: armv7m
  • Close dialog with Ok .

Select the following check boxes in the Cross tab:

  • CPU: arm
  • OS: embedded

Press the Install cross compiler button, the cross compiler will be built. If everything worked correctly, exit FPCUPdeluxe.

Prepare Lazarus

Start with F9

If you try to start with F9, you always get an error message. You can prevent this. Change the following in Lazarus:

  • "Tools > Settings ... > Keyboard layout > Commands from the menu 'Start' > Start program", set to Unknown.
  • "Tools > Settings ... > Keyboard layout > Commands from the menu 'Start' > Start without debugger", remove the ticks from Shift and Ctrl.

Now you can upload and start a program normally with F9, but consider that the debugger is also disabled if you then write a normal PC program with Lazarus!

Code tools

It may be that the code tools does not find the stm32f103xb unit. If so, then the following step is necessary:

  • "Tools > Reread FPC source code directory"

Readable ASM code creation

If you want to see the source as assembler code, the following step is necessary:

  • Enter "Project > Project Settings ... > User-defined settings > User-defined settings" -al, this creates an *.s file that contains the program as ASM code.

Faulty optimization

I have experienced a program not working properly because the compiler incorrectly optimised the code. So you should switch off code optimization with {$O-} at the beginning of the program.

First project

Create a new project

  • "File -> New ... > Simple Program" - create a new project.
  • "Project > Project Settings ... > Configuration and Goals" - set the following:
    • Target operating system (-T): Embedded
    • Target CPU family (-P): arm
    • Target processor (-Cp): ARMV7M
  • "Project > Project Settings ... > Debug" : Remove the check mark "Generate debugger information for GDB" .
  • "Project > Project settings ... > User-defined settings -> User-defined settings still enter -WpSTM32F103X8.
  • "Project > Project Settings ... > Compiler Commands -> Execute After"
    • Remove the Compile and Recompile ticks.
    • Enter the following into the command: st-flash write stm32Blink.bin 0x8000000
Light bulb  Note: The paths still have to be adapted to your own installations.

As a recommendation, I would take this project as a template and build all new projects on top of it. Setting the whole thing up for a new project each time is a bit tedious.

Start project

Nothing should now be standing in the way of your first blink program (source below). Compile and upload the program with F9. If everything worked, the LED at pin 13 should flash about every second.

program stm32Blink;


procedure delay;
  i : uint32;
  for i := 0 to 500000 do 
        nop   // empty instruction

  // turn on Port C
  RCC.APB2ENR := RCC.APB2ENR or (%1 shl 4);

  // Pin 13 from Port C to Output
  PortC.CRH := $00300000;

  // Note: The LED lights up at LOW.
  while true do 
      // Pin 13 - High
      PortC.BSRR := 1 shl 13;

      // Pin 13 - Low
      PortC.BRR := 1 shl 13;

Manually with make

Not tested.

  make clean all OS_TARGET=embedded CPU_TARGET=arm SUBARCH=armv7m

MSEide and MSEgui

As an alternative to Lazarus you can also use the MSEide and MSEgui.

The following tools are necessary:

Unzip these archives into a folder, eg /home/tux/STM3-FPC

Start MSEide under /home/tux/STM32-FPC/msegui/bin.

  • Settings > Configure MSEide
    • adjust the following path: ${MSEDIR} - /home/tux/STM32-FPC/msegui/
  • Project > open - Open the demo project in the extracted folder. (/home/tux/STM32-FPC/samples/embedded/arm/stm32l100c/stm32l100c.prj)
  • Project > Options > Macros, adjust the following paths:
    • TOOLCHAINDIR - /home/tux/STM32-FPC/gcc-arm-none-eabi-7-2017-q4-major/
    • CROSSFPCDIR - / home/tux/STM32-FPC/crossfpc-x86_64_linux_eabi_embedded_3_1_1/

If a red break point is set in the left column, deactivate it with a click. Start the program with F9. If everything went well, this should work without errors.

See also