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Associate II
October 29, 2025
Question

NUCLEO-U575ZI-Q + NUCLEO-IHM08M1

  • October 29, 2025
  • 3 replies
  • 238 views

I have been working with sensorless BLDC motor control using NUCLEO-U575ZI-Q + NUCLEO-IHM08M1. When I work with Motor Control Workbench I see this warning "IWConnect: BEMFSensingADC BEMF_V is not connected to any matching input (ADC[0-9]*)_IN(?!N)" 

Can anyone explain this? 

Is there any physical wiring needed? 

3 replies

GMA
Technical Moderator
October 30, 2025

Hello @Suthan,

At this point, the Workbench tool verifies all configurations. In this case, the BEMF_V signal ADC measurement for the 6-step feature is not feasible.
The 6-step feature is not supported on the STM32U5 series.

If you agree with the answer, please accept it by clicking on 'Accept as solution'.Best regards.GMA
SuthanAuthor
Associate II
October 30, 2025

@GMA 

It appears that only FOC is supported for the STM32U5 series. For sensorless FOC, the system still relies on BEMF signals, for rotor position estimation.
In STM32 Motor Control Workbench, I encountered the warning:
"IWConnect: BEMFSensingADC BEMF_V is not connected to any matching input (ADC[0-9]*)_IN(?!N)".
What is the recommended solution to resolve this warning when configuring sensorless FOC with STM32U5?

GMA
Technical Moderator
October 30, 2025

Hello @Suthan,

For more details about the FOC sensorless observer, refer to the User Manual documentation.
To use the FOC feature, select the Create button at this point.

If you agree with the answer, please accept it by clicking on 'Accept as solution'.Best regards.GMA
SuthanAuthor
Associate II
October 30, 2025

@GMA 

There seems to be a misunderstanding between my original question and your response.

I’ve already followed the recommended steps and selected Observer + PLL as the sensorless control mode in Motor Control Workbench. However, my question still stands: even after selecting this mode, the system prompts a warning indicating that three BEMF signals are required. I’m trying to understand why this requirement exists?

Suthan_0-1761837604874.png

 

GMA
Technical Moderator
October 30, 2025

@Suthan,

It is not a requirement but only a warning about SixStep BEMF measurement as described in section 3.2.5 BEMF sensing network of the Six-step firmware algorithm chapter of the user manual.

If you agree with the answer, please accept it by clicking on 'Accept as solution'.Best regards.GMA