Starting STM8 Microcontrollers

STM8S003K3 Discovery

Software Tools

Just like any other software developer, my choice of language for software development is C language. I don’t want to spend time coding complex stuffs in assembly or other languages. STM8s are also C optimized micros. Apart from these reasons, I chose C language for the fact that STMicroelectronics has provided a Standard Peripheral Library (SPL) that is very easy to use. With SPL, it becomes totally unnecessary to program each peripheral register with meaningless numbers and maintain coding sequence. We will never need to access registers for any reason as everything is done under the hood of SPL. All sequences are dealt inside the SPL. All that we will ever need is the clear concept of each hardware block, their working principles, their capabilities and limitations.

We will need an Integrated Development Environment (IDE) and a C-language toolchain. The best stuffs you can get your hands on at zero costs are ST Visual Develop (STVD) IDE and Cosmic C compiler. Both are free but a rather difficult to use at first. STVD also packs with a programmer software tool called ST Visual Programmer (STVP). We will need STVP to upload codes to target STM8 micros.

Cosmic used to be a paid tool just like your PC’s antivirus software but at the time of writing this article, the Cosmic team has made it absolutely free for STM8 family. However, to use it you will need to register and acquire a license key via email. Usually this procedure of acquiring license and registration is maintained automatically by the software company’s server but with Cosmic it is different story. You will need to wait for some guy at Cosmic end to respond to your license request. It may take a few minutes or even a day but still the best part is getting a full version compiler for nothing.


You can get
STVD from here: and
Cosmic C compiler from here:

You need to register in order to download both software. For Cosmic you will also need to acquire a free license for it work. So just fill in some basic info about you.


Firstly, we will need to install STVD. Installation procedure is simple and same as typical software installation. Just click next, next and next. After that we will need to install Cosmic C compiler. Again, just next, next and next until the screen as shown below.


After installation, you’ll prompted for licence. You must register your license unless you have already registered. If you have already registered, then you’ll be asked if to overwrite registration. You should skip reregistering.


For the first run, you’ll get the following screen looking for a valid license.


You must fill all the starred (*) points to complete the process of registration. Select “Write to File” option and save the file as a text (.txt) file. The file name should be “CM8_license.txt”. Send this file to with subject “STM8FSE, STM32 32K License Request”. Now you’ll need to wait for the Cosmic team to respond to you. They’ll send you an email back with an electronic key license. The file will have a name like “license.lic” and the email will have some instructions.

This was my emailed license.


Once you get the license, you’ll need to show the software its location and complete the licensing process as shown below. Save the license file in a secured location.




At the end of this process, we can enjoy the compiler without any limitations.

I also recommend that you download Sublime Text ( or Notepad++ ( for viewing your code with ease. These are very cool software. This is not mandatory though.


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  • SSI_Electronics

    I have followed the code as per the explanation.
    but I’m getting garbage values on serial port.
    Can you suggest any debugging steps??
    Thanks in advanced.

    PS: Great tutorial. It’s helping me a lot.

    • 1. Check wiring for loose connections….
      2. Use a stable and noise-free power source like a battery-bank to power up the board…. Noise from PC port may cause unwanted issues….
      3. Use CP2102 or FT232-based USB-TTL converter…. Don’t use PL2303-based ones because most are clones or fakes….
      4. Use a short USB cable….
      5. Use external pull-up resistors for both TX and RX pins….
      6. Try with another board if these don’t solve the issue…. It should not behave as you are saying because the code has no issues….

  • santosh kharade

    Serial receiving program is not working

  • Hello sir
    Do you tell me how generate pwm in pin no. B5 & B5
    in Stm8 board

    • Which STM8 chip? Because different chips have different pin mapping and sometimes there are alternative pins for such purposes…. Check with STM8CubeMX if that pin is available for that purpose….

  • Santosh Kharade

    i have done code for multi channel adc but its not working ????
    when i use single channel adc its working properly…………

  • Hello guys
    here i’m again for ask your help. I wrote a very easy program but when i try to send to stm8 the light programmer give me this error :

    >Erase not feasible
    Error: Device not recognized !

    some idea ?
    Thank you

  • First thank you so much for this wonderful tutorial, i’m new with STM8 i follow all you steps but i still have a problem and here i’m please can you help me this is the error message.
    Thank you

    ———– Project test_prov – STM8 Cosmic – Configuration Debug ————-

    Compiling main.c…
    cxstm8 -i..\..\en.stsw-stm8069\stm8s_stdperiph_lib\project\stm8s_stdperiph_template -igpio -iinc +debug -pxp -no -l +mods0 -pp -i”C:\Program Files (x86)\COSMIC\FSE_Compilers\CXSTM8\Hstm8″ -clDebug\ -coDebug\ main.c
    #error cpstm8 gpio\inc\stm8s.h:74 “Please select first the target STM8S/A device used in your application (in stm8s.h file)”
    The command: “cxstm8 -i..\..\en.stsw-stm8069\stm8s_stdperiph_lib\project\stm8s_stdperiph_template -igpio -iinc +debug -pxp -no -l +mods0 -pp -i”C:\Program Files (x86)\COSMIC\FSE_Compilers\CXSTM8\Hstm8″ -clDebug\ -coDebug\ main.c ” has failed, the returned value is: 1
    exit code=1.

    test_prov.elf – 2 error(s), 0 warning(s)

  • Hi Shawon ,
    Excellent article on stms8.
    within 3 days i was able to understand STMS8 very clearly.
    can you send me delay library files please.
    i tried to create my own without any success.
    warm regards

  • hi sir now also getting problem in compilation time …..’

    so plz can u send me the soft copy of software wat properly working at u…??

    my emain id…

    • I’m using the same software you are using – the latest one out there…. and so someone sending it has no meaning…. I suggest that you uninstall it and give it fresh retry, following all the steps carefully…. No one can help you with licensing issue unless to do it correctly….

  • hi geting poroblem while click on programmer ten my softare automatically close tab

  • hi sir…

    i getting problem for license configured……………. at compile time getting error like that…………. plz help out

    #error cpstm8 C:\Program Files (x86)\COSMIC\FSE_Compilers\CXSTM8\HSTM8\mods0.h:1 FlexLM Cannot find license file.
    The command: “cxstm8 -iinc +debug -pxp -no -l +mods0 -pp -i”C:\Program Files (x86)\COSMIC\FSE_Compilers\Hstm8″ -clDebug\ -coDebug\ main.c ” has failed, the returned value is: 1
    exit code=1.

    alpha_lcd.elf – 3 error(s), 0 warning(s)

  • helo…we hav stm8svl discovery..i need embedded c program for the glowing of led,connecting ir receiver and also powersupply…for connecting these things i need code can u please guide me

  • Thanks for this article..
    I am looking for microsd card interface with STM8s discovery board. can you please provide the tutorial for microsd card?

  • In relation to disabling unused peripheral clocks as suggested by you:

    I found the following list of peripherals in the STM8S105 Discovery Board: Advanced control timer (TIM1), General-purpose timers (TIM2 and TIM3), Basic timer (TIM4), SPI, I2C, UART2, Window WDG, Independent WDG, ADC1,
    AWU timer, Beeper.

    Is this all?

    I could not find the clock peripheral configuration function for Window WDG, Independent WDG, Beeper in the Standard Peripheral Library.
    Is it not required?

    P.S. I am new to MCU programming with a little experience on Arduino. So please forgive me if the question is foolish.

    • 1. STM8S003K3 Discovery – the one I use for the blog is different from STM8S105…. They have different peripherals and so there will be differences in peripheral clocks…. Please check the device datasheet/STM8CubeMX for available hardware….

      2. WWDG and IWDG are set in option bytes and they don’t use peripheral/CPU clock…. Their oscillator is separate…. Due to these they don’t have clock configurations like other peripherals….

      P.S: No question is a noob question…. every question is allowed no matter how silly it may look….

  • Hi please someone tel me where can i find stm8s_delay.h and stm8s_delay.c

  • Hi , please someone tel me . Where can i find stm8s_delay.h and stm8s_delay.c
    Thanks ..

  • i am using stms003f3p6 controller..i have done as u told exactly but tim1 input capture is not displaying any value …according to your article it should display 10…i dont have any errors everything is fine…pulse on tim2 is ok is coming as u said…but capture not working..please help me …thank you…

  • Hi Sir,
    i have just follwed your instruction provied in yout tutorial in main.c

    #include “stm8s.h”

    while (1);

    This error comes, can you please check why this error come, i am new and learn the controller programming.

    The command: “cxstm8 -i”d:\other datasheet\new folder\lib\stm8s_stdperiph_lib\libraries\stm8s_stdperiph_driver\inc” +debug -pxp -no -l +mods0 -pp -i”C:\Program Files (x86)\COSMIC\FSE_Compilers\CXSTM8\Hstm8″ -clDebug\ -coDebug\ main.c ” has failed, the returned value is: 1
    exit code=1.

    main.o – 2 error(s), 0 warning(s)


  • Hi there, i solve the previous ADC problem. Anyway, u make some good tutorial on stm8 chips. Nice work

    • What was causing that issue? How did you solve it?

      • because i put all these

        ADC_SamplingTimeConfig(ADC1, ADC_Group_SlowChannels, ADC_SamplingTime_4Cycles);
        ADC_SchmittTriggerConfig(ADC1, ADC_Channel_7, DISABLE);
        ADC_ChannelCmd(ADC1, ADC_Channel_7, ENABLE);
        ADC_Init(ADC1, ADC_ConversionMode_Continuous, ADC_Resolution_12Bit, ADC_Prescaler_1);
        ADC_Cmd(ADC1, ENABLE);
        ADC_ExternalTrigConfig(ADC1, ADC_ExtEventSelection_None, ADC_ExtTRGSensitivity_All);

        in ‘while(1)’. It keeps looping.

        Once i put it before ‘while (1)’, it becomes normal.

  • Hi there, thanks for sharing. I learn alot thru your example, but I have encounter a problem with adc. Im currently using stm8l151k4t6. I wanna use the pin D7 as to read the voltage from my battery and monitor it (display on LCD). Can u please check where it goes wrong on my code?

    ADC_SamplingTimeConfig(ADC1, ADC_Group_SlowChannels, ADC_SamplingTime_4Cycles);
    ADC_SchmittTriggerConfig(ADC1, ADC_Channel_7, DISABLE);
    ADC_ChannelCmd(ADC1, ADC_Channel_7, ENABLE);
    ADC_Init(ADC1, ADC_ConversionMode_Continuous, ADC_Resolution_12Bit, ADC_Prescaler_1);
    ADC_Cmd(ADC1, ENABLE);
    ADC_ExternalTrigConfig(ADC1, ADC_ExtEventSelection_None, ADC_ExtTRGSensitivity_All);
    while(!ADC_GetFlagStatus(ADC1, ADC_FLAG_EOC));
    battery = ADC_GetConversionValue(ADC1);

  • hi shawon great tutorials it would be nice too if you covered the coide compiler for arm it’s a good free compiler

  • hi shawon thanks for your response and support it turns out that my problem was a license issue I stupidly thought i use one license on multiple pc’s I used the license for a particular computer for mine that’s why I’ve been having compilation issues you have to use the license file stm8 sends you that is generated by your own pc else it won’t compile it’ll jus kip throwing you errors

  • It seems that you didn’t follow my instructions completely…. I found some issues:

    1. You have included header and source files of ADC2, CAN, UART2, etc which are unavailable in STM8S103…. Add only files for the peripherals available in your target MCU…. Exclude the rest….

    2. You have not included stm8s_delay header and source files…. Either disable it from stm8s_conf.h header file if you are not going to use it or add both the header and the source files for it in your project….

    Resolve these and you are good to go….


  • I haven’t compiled any of the examples yet I just tried to compile the main source file just for test purpose n it just keeps showing me the same errors

  • yes the comic compiler was installed properly i even received a license file from my mail with the instructions to copy the license file to the license folder in the install directory if you fail to do this it will keep popping up for you to put in the license file. iincluded all the source files and header files as instructed i am working with the cheap stm8s103f i uncommented the stm8s103f in the stm8.h header file as you instructed and just to compile the main file it just throws me errors

  • no I just followed your instructions I just compiled it after setup i did not write any code yet just compiled the default main file

    • Need more details….

      1. The version of STVD and Cosmic
      2. Which example is giving this issue?
      3. The chip you are using if it other than STM8S003
      4. Have you tried to compile something else other than my examples?
      5. Are the paths to libraries and other folders properly added?
      6. Is the Cosmic compiler registered properly?

  • it throws this line The command: “cxstm8 -iinc +debug -pxp -no -l +mods0 -pp -i”C:\Program Files (x86)\COSMIC\FSE_Compilers\Hstm8″ -clDebug\ -coDebug\ main.c ” has failed, the returned value is: 1
    exit code=1.

  • hi I’m having compilation issues when I compile it just throws me error about comic compiler located in the program file ialso excluded unwanted header files but my problems still weren’t solved

  • hi thanks for the tutorials but i am having compiler error issues even when I remove unnecessary header files it say comic compiler error

  • I am new to STM8S003k3 Discovery board.I have done UART communication using STM standard peripheral library example. Now I want to define any other GPIO pin for UART communication. Is it possible to use d0 and d1 pin for the UART communication? If yes, then please let me know how?

  • thank you very much for this article!

  • Thank you for your time and effort.

  • Good job bro

  • Thank you for this exceptionally comprehensive article, much appreciated


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