TMS320F280049C: Removing an offset using the PBB

UserHomeInit

Part Number: TMS320F280049C

Dear TI hello,

I use this code to remove an offset,

void
vDrvadc_SetupPPBOffset(int16 aOffset, int16 bOffset, int16 cOffset)
{

    /*
     * PPB1 is associated with SOC1
     * PPB1 will subtract OFFCAL value
     * to associated SOC
     * */
    ADC_setupPPB(ADCA_BASE, ADC_PPB_NUMBER1, ADC_SOC_NUMBER0);
    ADC_setPPBCalibrationOffset(ADCA_BASE,ADC_PPB_NUMBER1 , aOffset);

    /*PPB1 is associated with SOC1
     *PPB1 will subtract OFFCAL value
     *to associated SOC
     * */
    ADC_setupPPB(ADCB_BASE, ADC_PPB_NUMBER1, ADC_SOC_NUMBER0);
    ADC_setPPBCalibrationOffset(ADCB_BASE,ADC_PPB_NUMBER1 , bOffset);

    /*PPB1 is associated with SOC1
     *PPB1 will subtract OFFCAL value
     *to associated SOC
     * */
    ADC_setupPPB(ADCC_BASE, ADC_PPB_NUMBER1, ADC_SOC_NUMBER0);
    ADC_setPPBCalibrationOffset(ADCC_BASE,ADC_PPB_NUMBER1 , cOffset);

}

I am using the PBB to remove an offset of 48, my issue is it looks like the PBB is not activated and the offset still existing?

Thank you in advance,

S.Tarik

over 4 years ago

0 Aditya Dholakia over 4 years ago

TI__Expert 7150 points

Hi S.Tarik,

By default all the PPB blocks point to SOC0. There are chances that, as per priority, the higher order PPB's (i.e PPB2, PPB3, PPB4) offset will be considered over PPB1. Can you check by changing the SOC0 to SOC1?

Thanks,

Aditya

0 UserHomeInit over 4 years ago in reply to Aditya Dholakia

Expert 2195 points

Thank you Aditya,

This resolved my issue but I didn't understand your explanation, could please clarify.

Thank you;

0 Aditya Dholakia over 4 years ago in reply to UserHomeInit

TI__Expert 7150 points

Hi S. Tarik,

The 4 PPB blocks by default are linked to work on SOC0 with priority of PPB4 offset being highest and PPB1 being lowest. So, while using PPB1 with SOC0, the offset of PPB1 may be overwritten with any of the higher order PPB offset, which is not desired. That is why it is better to avoid using SOC0 to avoid unintentional overwriting.

You may find some literature on this in the PPB section of the Technical Reference Manual for the device as well.

Hope this helps.

Thanks,

Aditya

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TMS320F280049C: Removing an offset using the PBB