Question

What are the actual steps that are followed in identifying any key that is being pressed?

(a) wait for the debounce time

(b) identify the key that is pressed

(c) initially no key should be pressed

(d) all of the mentioned

I have been asked this question in an interview for internship.

I need to ask this question from Keyboard Interfacing topic in portion AVR Microcontroller of Microcontroller

Answer 1

Correct option is (d) all of the mentioned

The explanation is: In order to identify that which key is actually pressed form a particular format of a 3*3 matrix keyboard, we firstly ensure all initially all the keys are open, then we press a key and check that whether the key is actually pressed or not by waiting for a time span of 20mseconds, after this we identify the key that is pressed by masking the bits of the port. In this particular format, we can identify the key that is actually pressed.