Microprocessors Module 3 - I/O Device Interfacing

Questions and Answers

What is the purpose of the `pinMode` function in the Arduino code?

To delay execution of the program

To read the value from a pin

To define the state of a pin as either input or output (correct)

To turn an LED on or off

In the digital input example, what happens when the pushbutton is closed?

The input pin reads LOW

The input pin reads HIGH and turns on the LED (correct)

The LED blinks at a high frequency

The LED turns off immediately

Which component is used to control high current loads in Arduino projects?

Capacitor

MOSFET or transistor (correct)

Diode

Resistor

Which function in the code is used to keep the LED on for a second?

delay Signup and view all the answers

What is the maximum current output of the Arduino's standard digital pins?

40mA Signup and view all the answers

What does the `digitalWrite` function do in the examples provided?

Writes a digital value to a pin, either HIGH or LOW Signup and view all the answers

What variable is used to represent the LED pin in the digital output example?

ledPin Signup and view all the answers

How does the code control a MOSFET to manage higher current loads?

By turning it on and off rapidly Signup and view all the answers

What is the role of the `void setup()` function in Arduino programming?

To initialize the settings before the loop runs Signup and view all the answers

Study Notes

Interfacing of I/O Devices

Various devices can be interfaced with microcontrollers, enhancing their interaction capabilities.
Manipulating microcontroller ports allows for data input (from sensors) and output (to actuators).

Digital Output

A basic program to toggle an LED on and off demonstrates digital output.
LED connected to pin 13 blinks every second using digitalWrite function.
Built-in resistor for pin 13 allows direct connection to an LED without additional circuitry.

Digital Input

Digital input has two states: HIGH (on) and LOW (off).
Example uses a pushbutton connected to pin 2; closing the switch reads HIGH and activates the LED on pin 13.
digitalRead function checks the state of the input pin to control the LED.

High Current Output

Controlling loads over 40mA from Arduino requires using a MOSFET or transistor for handling higher current.
Example turns a MOSFET on and off five times per second to control a motor.
Implementation may include protective components like a diode for non-inductive loads.

Analog Output

Example demonstrates controlling LED brightness using PWM (Pulse Width Modulation) via analogWrite.
Variable delayVal() can be used to modify brightness dynamically.
Loop structure allows for gradual changes in LED intensity, enhancing visual feedback through gradual dimming effects.