Question

What is the use for the 2 serial pins on the Arduino Diecimila?

(a) To send and receive GPIO digital signals

(b) To receive analog signals

(c) To send PWM signals

(d) To send and receive Serial TTL signals

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

This key question is from Board Pinout Structure in portion Board Specifications and Types of Arduino

Answer 1

Correct option is (d) To send and receive Serial TTL signals

The best explanation: There are two pins for sending and receiving the Serial TTL Signals. The TX (for transmission) and the RX (for receiving). In the Arduino Diecimila they are connected to the corresponding pins of the FTDI USB to Serial Chip.