To identify that which key is being pressed, we need to:
(a) ground all the pins of the port at a time
(b) ground pins of the port one at a time
(c) connect all the pins of the port to the main supply at a time
(d) none of the mentioned
I got this question during an online interview.
Question is from Keyboard Interfacing in division 8051 Microcontroller of Microcontroller