Nucleo-F072RB Serial port not working

[dyMath6]

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.

[Andrew Neil]

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.

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@dyMath6 wrote:

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

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

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@dyMath6 wrote:

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

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

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@dyMath6 wrote:

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

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

[dyMath6]

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 

[unsigned_char_array]

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?

[Andrew Neil]

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@dyMath6 wrote:

I checked the COM port in my settings  

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Did you check in Device Manager that the COM port is there and on the expected COMx number?

Make sure that your terminal is set for NO flow control 

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@dyMath6 wrote:

my problem must come from my personal computer 

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Indeed.

Do you have another Nucleo board to try?

and/or a standalone USB-to-UART converter?

Does the debug connection to the ST-Link work?

[dyMath6]

Hi, 

I'm on a laptop, I only have two USB port, and I can see my nucleo in the device manager with both. 

I checked for viruses and it seems to be good, I'm left with the port drivers though I'm not sure where to look for that

[dyMath6]

The COM port is in Device Manager but I'm not sure what you mean by "expected COMx number", I usually configure putty based on what I see in Device Manager, if you mean is it the same as before, I can't remember.

I checked for no flow control, it didn't change.

I'll try with another nucleo.

And yes the debug connection to the ST-Link works

[Karl Yamashita]

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.