Hi, I bought a Nucleo STM32F401RE board. Yeasterday the board was working fine in dimming led in A0 pin which was configured in PWM mode. Now I can't reprogram the board. See details for error message. PS. I'm a total beginner with microcontrollers

[VNisk.1]

Starting server with the following options:

    Persistent Mode      : Disabled

    Logging Level       : 1

    Listen Port Number     : 61234

    Status Refresh Delay    : 15s

    Verbose Mode        : Disabled

    SWD Debug         : Enabled

    InitWhile         : Enabled

Target Held under Reset

Error in initializing ST-LINK device.

Reason: Target held under reset.

[Imen.D]

Hello @VNisk.1​ and welcome to the Community :)

Is BOOT0 pulled LOW?

Check the power VDDA​, and don't pull NRST low.

If a post answers your question, please close this topic by choosing "Select as Best" on that post.

This will help other users find that answer faster.

Imen

[VNisk.1]

At the moment there is nothing connected to the Nucleo board.

I' will try to connect the BOOT0 to GND.

Should I let the NRST be unplugged or connect it to 3,3V?

What do you mean with "check power VDDA"?

[TDK]

"Target held under reset" suggests NRST is being held low. You should not be connecting this pin to anything, and certainly not driving it to 3.3V.

Can STM32CubeProgrammer connect?

[VNisk.1]

The STM32CubeProgrammer connected when I set the ST-Link mode: Hot plug. Still the Full chip erase fails.

Other modes have the same problem as earlier descriped.

[VNisk.1]

I tried connecting BOOT0 to GND.

(CUBE programmer with SWD, normal, hardware reset)

Error: No STM32 target found!

So the problem still exists?

[Piranha]

Use "Connect Under Reset" mode.

[VNisk.1]

I tried that. Still getting the same response: "Error: No STM32 target found!"

[VNisk.1]

Should the be a 3,3 voltage in NRST pin. as far as I can tell the pin is low all the time. (Connected it led without resistor and still nothing).

Do you think the board maybe faulty?

[TDK]

A multimeter would be a better test. The pull-up is small and may not visibly drive an led.