Question

Why Vref is set of ADC0848 to 2.56 V if analog input is connected to the LM35?

(a) to set the step size of the sampled input

(b) to set the ground for the chip

(c) to provide supply to the chip

(d) all of the mentioned

The question was posed to me in a national level competition.

This key question is from Sensor Interfacing topic in chapter 8051 Microcontroller of Microcontroller

Answer 1

Correct answer is (a) to set the step size of the sampled input

To elaborate: Vref is used to set the step size of the ADC conversion, if it is selected to 2.56 then the step size will be selected to 10mV, so for every step increase of the analog voltage an increase of 10 mV will be there.