Question

Why two pins for ground are available in ADC0804?

(a) for controlling the ADCON0 and ADCON1 register of the controller

(b) for controlling the analog and the digital pins of the controller

(c) for both parts of the chip respectively

(d) for isolate analog and digital signal

I have been asked this question during an interview.

This is a very interesting question from ADC, DAC Interfacing in section 8051 Microcontroller of Microcontroller

Answer 1

Right option is (d) for isolate analog and digital signal

To explain I would say: Two grounds are available in ADC0804 to isolate analog signal from digital signal. This isolation provides accuracy in digital output.