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TMS320F28377D SDFM with FILRESEN enabled.

GINILY
Intellectual 445 points


Hi all,

I am using F28377D SDFM module for reading the current feedback.

I have tested acquiring SDDATA with and without FILRESEN enabled. But the SDDATA results are different, e.g. read -11186 without "FILRESEN enabled", and -2164 with "FILRESEN enabled'. I have used SD ISR (SDDFPARM1. AE = 1) to read the SD Data. The non Sync reset result is correct (matched SDFM SD1_D1 input). 

I need to sync the SDFM to the PWM module for proper current measurement. Please help.

Thanks,

Lily.

  • 0
    TI__Guru 55700 points

    Lily,

    When FILRESEN is enabled, PWM sync pulse will reset the SDFM data filter on a periodic basis depending upon how the PWM is configured.

    Each time the SDFM data filter is reset, depending upon the filter type first few samples will be incorrect and all subsequent samples will be correct until it is reset again.

    Sinc1 filter type - No incorrect sample

    Sinc2 filter type - First sample will be incorrect

    Sinc3 and SincFast - First 2 samples will be incorrect.

    This is due the inherent nature of the Sinc filter architecture and it is not a bug.


    Regards,

    Manoj

  • 0 in reply to Manoj Santha Mohan
    Intellectual 445 points

    Hi Manoj,

    Thanks for the reply. We will try to work around this to avoid these incorrect samples.

    Lily.