First motor start fails with SPEED_FEEDBACK fault, second start works

[ElGuerrero91]

Hi,

I’m experiencing a consistent issue with the STM32 Motor Control SDK:

• The first motor start attempt always fails with a MC_SPEED_FDBK fault
• After acknowledging the fault, the second (or further) start attempts work perfectly

Observations:

• During the first start, there is no audible motor movement
• Current signals (I_q_ref / I_q_meas) look misaligned or not properly regulated
• After the first failed attempt, signals stabilize and the motor starts normally
• The MC state is initially IDLE
• Fault reported: 0x0020 (MC_SPEED_FDBK)

Observations:

• During the first start, there is no audible motor movement
• Current signals (I_q_ref / I_q_meas) look misaligned or not properly regulated
• After the first failed attempt, signals stabilize and the motor starts normally
• The MC state is initially IDLE
• Fault reported: 0x0020 (MC_SPEED_FDBK)

It seems like something is not fully initialized/calibrated on the first start, possibly:

• Current sensing / ADC offset calibration

My Setup:

SW in Release Mode

Target: Custom Board based on EVSPIN32G4 Schematic (EVSPIN32G4)

Chip: STM32G431VBx3. 

MCSDK 6.4.1

FOC / Sensorless

[GMA]

Hello @ElGuerrero91,

Did you enable the driver protection on the MCU side to check the nFAULT signal (see STSPIN32G4 document, PE15 input)?

VDS monitoring can trigger the nFAULT signal and prevent PWM generation. You can disable VDS monitoring by connecting the SCREF input to VDD.