Sar ADC''s output code

AlVa_264671 · ‎Jul 27, 2018

Hi there

I always used ADC Delta sigma. This is my firs time with Sar ADC.

I have attached a simple project where the minus Sar's input is hooked up to Vref/2

From a pot I change the + input volatge between Vssa and Vdda.

I don't know what I am missing but I expect get negative values when V+ - V- is negative and positive values when the diference is positive.

I just got values from 0 couts to 4095 counts when the positive input is from 0v to 3.3v ,in this case.

Please see attached project.

Thank you in advance

Vasanth · ‎Jul 29, 2018

Hi Alejandro,

The problem with your code is that ADC_SAR_1_SAR_WRK0_PTR register is not sign extended; the result is always unsigned. You can use ADC_SAR_1_GetResult16(); API inside the ISR which will return a signed result .

Best Regards,

VRS

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Sar ADC''s output code

Sar ADC''s output code

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