RM57L843: ADC

VEERAPPAN P

Part Number: RM57L843

Hi team,

I am using RM57L843 microcontroller, I have doubts on ADC. To calculate digital result their is a equation is given below. In that equation why subtracting 0.5 ?

over 2 years ago

+1 jagadish gundavarapu over 2 years ago

TI__Guru 72836 points

Hi Veerappan,

Look into the below thread, here QJ explained why 0.5 subtraction is required.

(+) RM44L520: ADC conversion result Equation question - Arm-based microcontrollers forum - Arm-based microcontrollers - TI E2E support forums

What QJ saying here is, consider the condition of

Now the DigitalResult for 12bit ADC will becomes as below.

That is,

DigitalResult = 4096-0.5

So, the conclusion is if we didn't use 0.5 then we will get the output as 4096(0x1000) which is more than 12bit result. If we use 0.5 then the output will be 4095(0xFFF) which is exactly 12bit.

For simplicity, you can also neglect 0.5 and use the formula like below.