Skip to main content
Visitor II
October 31, 2025
Question

Nucleo-F072RB Serial port not working

  • October 31, 2025
  • 3 replies
  • 514 views

Hi, I'm a student quite new with STM, I am using a nucleo F072RB and I have been unable to print anything onto putty for a few weeks, it was working fine before summer break but not anymore (I haven't used my nucleo during that time), I am using the same baud rate and same port com as before, I tried to run my older projects that use putty and same result, nothing appears. I have no idea what to do to try to solve it, please help. Thanks.

    This topic has been closed for replies.

    3 replies

    Super User
    October 31, 2025

    Welcome to the forum.

    Please see How to write your question to maximize your chances to find a solution for best results.

     

    How are you connecting to PuTTY - are you using the ST-Link VCP ?

    You need to use a full data cable - not just a charging cable.

    Try other cables.

     


    @dyMath6 wrote:

    it was working fine before summer break but not anymore (I haven't used my nucleo during that time).


    and you're sure that nobody else has touched it ?

     


    @dyMath6 wrote:

    I am using the same baud rate and same port com as before,


    Might be worth checking that the board is still on the same COM port

     


    @dyMath6 wrote:

     I have no idea what to do to try to solve it, please help. Thanks.


    First thing would be to use an oscilloscope to check that data is actually emerging from the STM32 at the correct rate

    dyMath6Author
    Visitor II
    October 31, 2025

    Thank you for you answer, 

    I am using the ST-Link VCP, and I checked the COM port in my settings thousands of times, but I tried connecting the nucleo to one of my uni computer and putty worked just fine (I didn't change anything except the Port COM, didn't upload anything else) so my problem must come from my personal computer 

    Graduate II
    October 31, 2025

    So we can conclude the MCU is sending serial data when connecting to the university PC.
    Assuming the same firmware on the MCU and the same cable it should work on your PC.
    What can potential problems be?


    USB port issues. Voltage and/or power. Are you sure the board is powered and is in device manager the programmer is visible? If not try a different USB port. If you use a hub or front USB port that can cause issues, so use an USB port on the back of your PC.

    Are you sure you have the right serial port number?

    Serial port driver/programmer firmware. Windows sometimes updates drivers automatically to a nonworking version. Especially if a non-genuine chip is used or the firmware of the programmer is not compatible with the driver.
    Look up the firmware of the programmer and the version of the driver on both your PC and the university PC.

    Virus scanner?

    Graduate II
    October 31, 2025

    Something must have change since then.

    Check JP6 to be sure the voltages are 3.3V for both Tx and Rx. Then check with an oscilloscope for data activity when sending or receiving data.

     

    Or, try starting a new clean project and just enable the USART2 and do a simple print. 

    Graduate II
    November 1, 2025

    @Karl Yamashita wrote:

    Check JP6 to be sure the voltages are 3.3V for both Tx and Rx. Then check with an oscilloscope for data activity when sending or receiving data.

    Or, try starting a new clean project and just enable the USART2 and do a simple print. 


    The firmware of the MCU or the hardware of the board is not the issue since it works on a different PC.

    Super User
    November 3, 2025

    Have you tried the oscilloscope test yet to see if there is any activity?

    Your NUCLEO-F072RB board has a jumper - CN3 - on the ST-Link section where you can probe:

    AndrewNeil_0-1762165321796.png

     

    Also probe on the Arduino CN9 header:

    AndrewNeil_1-1762165505439.png

    (and/or CN10).

     

    Do you see activity on TX when the STM32 is transmitting ?

    Do you see activity on RX when the terminal is transmitting ?

     

    PS:

    If you disable the TX & RX pins on the STM32F072 Target, you can put a jumper on CN3 and do a loop-back test from the terminal.

    Super User
    November 3, 2025