Issue Connecting STM32H745BIT6 Custom Board with STLINK-V3SET Debugger

[Prathiksha]

Hi Team,

We are currently working with a custom board that uses the STM32H745BIT6 MCU, and we are attempting to connect it to the STLINK-V3SET debugger. However, we are experiencing intermittent debugging issues described below:

1. The debugger successfully enters debug mode only 2–3 times when done the first time.

2. In most cases, the debugger connects and enters debug mode, but after approximately 6–8 seconds, it displays a “Target lost” error (please refer to the attached photo).

3. Often, it shows “Target not responding.” When this happens, we need to power cycle the board. After turning the power supply off and on again, it behaves as described in point 2.

This issue has become a major roadblock in our development process.

Could you please advise if we might be missing something or configuring anything incorrectly? If you require any additional information from our side (errors, logs, etc.), please let us know and we will provide it.

Best regards,
Prathiksha

[mƎALLEm]

Hello,

Check the VCORE voltage level versus the VOS you set and the power supply config in your software versus what is provided in the datasheet:

Ensure you have followed the hardware guidelines described in the application note AN4938 "Getting started with STM32H74xI/G and STM32H75xI/GMCU hardware development" especially the VCAP part:

[Prathiksha]

Yes. These conditions are satisfied.
Attached the screenshot for your reference.

[mƎALLEm]

What about my first question? you need to monitor the Vcore voltage.

[Prathiksha]

But how do we check that?

[mƎALLEm]

Measure VCAP voltage with an oscilloscope and check if there is a glitch / voltage drop.

[TDK]

This is likely a hardware design problem.

Why are there two grounds?

[Prathiksha]

I checked that with the hardware team, that is no issue.

[Prathiksha]

Hi,

We checked the board and observed that VCAP is at 1.1V. However, there is no output voltage from the SMPS; it is reading 0V.

Please note that the MCU memory has been erased.

Could you also confirm whether any specific software configuration or initialization is required to enable the SMPS output? We would like to verify if the 0V condition could be due to a missing configuration setting.

Kindly let us know your input on this.

Best regards,
Prathiksha

[Prathiksha]

We would really appreciate your support at the earliest, as this issue is currently blocking our progress.