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fontys_student
Associate
January 16, 2024
Question

stm32 I2c won't send data

  • January 16, 2024
  • 7 replies
  • 4279 views

I am trying to get to use I2C on my stm32L4R5ZIT-P.

i am trying to configure a sensor by sending data but the I2C pins wont give a signal?

i dont ude interups or DMA

these are the pins that i use and the setting for I2C:

fontys_student_2-1705416583285.png

 

fontys_student_1-1705416526079.png

this are the includes i use

fontys_student_3-1705416909107.png

this is my code. i don't have any errors or warnings in the code

fontys_student_4-1705416964693.png

how do i fix it and make shure i can send data out?

 

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    7 replies

    TDK
    TDK
    January 16, 2024

    Does HAL_I2C_IsDeviceReady return HAL_OK? Do your other functions return HAL_OK?

    "If you feel a post has answered your question, please click ""Accept as Solution""."
      fontys_studentAuthor
      Associate
      January 17, 2024

      i am new to the stm platform. where can i see if the functions give a HAL_OK

      Andrew Neil
      Andrew Neil
      Super User
      January 17, 2024
      @fontys_student wrote:

       where can i see if the functions give a HAL_OK

      It will be the return value from the function call; eg, 

      HAL_StatusTypeDef result; // for the return value from HAL function calls

result = HAL_I2C_IsDeviceReady( &hi2c2, 0x40<<1, 10, 1000 );

       

      BTW: rather than writing `0x40<<1` as a Magic Number, it would be better style to give it a meaningful name; eg,

      #define SENSOR_I2C_ADDRESS (0x40<<1)

      then you can write:

       

      result = HAL_I2C_IsDeviceReady( &hi2c2, SENSOR_I2C_ADDRESS, 10, 1000 );

       

      Which is not only clearer & easier to understand, but also easier to maintain; eg, if you find that the address needs changing...

       

      A complex system that works is invariably found to have evolved from a simple system that worked.A complex system designed from scratch never works and cannot be patched up to make it work.
      Bob S
      Bob S
      Super User
      January 16, 2024

      What do you mean "won't give a signal"?  Are you looking at the SDA and SCL lines with a scope or logic analyzer?

      "I don't have any errors or warnings in the code" -> means no compiler errors or warning.  You need to check the return values from the HAL calls. Do you call MX_I2C2_Init() somewhere before the code you posted?

      Is this a custom board or one of the ST Nucleo (or Disco?) boards?  Are there external pull-up resistors on the SCL/SDA lines?  Using only the STM32's internal pull-ups MAY work for testing but should not be relied on in a production device - they are too high a resistance.

      Also, when posting code, please don't post images, copy/paste the code into the forum message using the code tags (click on the "..." button then "</>").

        Andrew Neil
        Andrew Neil
        Super User
        January 17, 2024

        UM1884 - Description of STM32L4/L4+ HAL and low-layer drivers:

        https://www.st.com/resource/en/user_manual/um1884-description-of-stm32l4l4-hal-and-lowlayer-drivers-stmicroelectronics.pdf

        See also https://www.st.com/en/microcontrollers-microprocessors/stm32l4r5zi.html#documentation for further documentation - Application Notes, etc ...

        A complex system that works is invariably found to have evolved from a simple system that worked.A complex system designed from scratch never works and cannot be patched up to make it work.
        TDK
        TDK
        January 17, 2024

        Start with blocking functions. Call HAL_I2C_IsDeviceReady and ensure it returns HAL_OK before calling any other I2C function. Don't call HAL_I2C_EnableListen_IT at the start.

        "If you feel a post has answered your question, please click ""Accept as Solution""."
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