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LMehm
Associate III
April 1, 2026
Solved

Unable to connect debugger/programmer.

  • April 1, 2026
  • 2 replies
  • 329 views

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.

Best answer by Andrew Neil

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 ?

2 replies

AScha.3
Super User
April 1, 2026

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.

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LMehm
LMehmAuthor
Associate III
April 1, 2026

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

Andrew Neil
Super User
April 1, 2026

@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

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.
Andrew Neil
Andrew NeilBest answer
Super User
April 1, 2026

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 ?

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.
LMehm
LMehmAuthor
Associate III
April 1, 2026

We don't have access to BOOT0 pin.

Andrew Neil
Super User
April 1, 2026

So what about NRST ?

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.