RM44L520: ADC conversion result Equation question

Eric Ma

Intellectual 2630 points

Part Number: RM44L520

Hi Champion

customer have a question about the equation:

Why it need to subtract 0.5?

Thanks.

Eric

over 8 years ago

0 QJ Wang over 8 years ago

TI__Guru**** 199196 points

Hello Eric,

The resolution of the ADC is 12bit. The ADC output code for the analog input voltage equal to ADrefhi is 0xFFF (4095). From the formula, the digital result = integer(0x1000-0.5) & 0xFFF = (0xFFF) & 0xFFF = 0xFFF. If we remove the 0.5 from the formula, the digital result = integer(0x1000) & 0xFFF = 0x0 which is not correct. This is my understanding. I will check with our ADC expert for the right answer next week.

0 Eric Ma over 8 years ago in reply to QJ Wang

TI__Intellectual 2630 points

Thanks Qingjun.
Eric

Arm-based microcontrollers

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RM44L520: ADC conversion result Equation question