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siungsuestone
Associate
January 6, 2026
Question

Are STM32G4 FMAC X and Y buffers cleared by HAL_FMAC_FilterStop ?

  • January 6, 2026
  • 1 reply
  • 170 views

Code Order :1、HAL_FMAC_FilterPreload_DMA。

2、HAL_FMAC_FilterStart。

3、HAL_FMAC_FilterStop。

4、HAL_FMAC_FilterStart。

5  HAL_FMAC_AppendFilterData

    i want ask ,does Fmac X and Y buff will clean when step3: HAL_FMAC_FilterStop function excute ?  

1 reply

Technical Moderator
January 22, 2026

Hello @siungsuestone 

At FilterStop, the internal X1 and Y FMAC buffers are not cleared.

However, their respective internal write and read pointers are reset to the X1_BASE and Y_BASE addresses.

When you restart the filter, the new data are computed using possibly outdated X & Y values (for an IIR filter).

If you want to keep the filter context and continue filtering with new data, do not stop the filter; just append a new data buffer by calling HAL_FMAC_AppendFilterData.

Otherwise, if for any reason, you must stop the filter, then restart it with the previous context by preloading the latest X & Y values.

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