Unable to connect debugger/programmer.

[LMehm]

Hello,

We programmed our STM32L011 microcontroller with firmware that enters STOP mode and waits for an interrupt.

However, we accidentally disabled the interrupt on the PA4 line. As a result, the device now immediately enters STOP mode, and we are unable to reprogram it.

Could you please advise how we can recover the device in this situation?

Thank you in advance.

[AScha.3]

Hi,

>We programmed our STM32L011

How ?

-- using a st-link on swd/swc ?    So just connect with CubeProgrammer and set mode : under reset + hardware reset.

[Andrew Neil · Accepted solution]

This is where it pays to include NRST in your debug connection - connecting under hardware reset would get you out of this state.

Do you have access to BOOT0 ?

[LMehm]

We are using ST-Link V2 and protocol is SWD.

[Andrew Neil]

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@LMehm wrote:

We are using ST-Link V2 

---

But have you connected NRST to it?

Is it a genuine one ?

How to recognize a genuine ST-LINK/V2 versus a cloned one

[LMehm]

We don't have access to BOOT0 pin.

[Andrew Neil]

So what about NRST ?

[LMehm]

Yes NRST is connected but Under reset mode didn't help.

[Andrew Neil]

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@LMehm wrote:

We don't have access to BOOT0 pin.

---

You said you "fixed" your previous problem by connecting it to ground.

So you could just remove that connection ?

Correction: You disabled it with option bytes.

The following still applies:

Rather than hard-wire it to ground or disable it with option bytes, a better approach would be to use a pull-down resistor - then you would still be able to pull it up when required ...

[LMehm]

We succeeded using Connect under reset mode.

Thank you!