PIC Microcontroller Basics

Questions and Answers

What is the purpose of connecting an inverted polarized diode to a coil?

To emit light when current flows.

To increase the current flow through the coil.

To create a short circuit across the coil.

To prevent high voltage self-induction. (correct)

How can a LED diode be permanently destroyed?

By connecting it upside down to the power supply. (correct)

By connecting it properly to the power supply.

By applying incorrect voltage for an extended period.

By exceeding its nominal current specification.

What happens to a LED if its nominal current specification is exceeded?

It will operate normally without consequence.

It can be destroyed or damaged. (correct)

It will stop emitting light temporarily.

It will emit light brighter than normal.

In the context of electrical components, what is self-induction?

The sudden change in voltage caused by stopping current flow. Signup and view all the answers

What component is used to protect against high voltage peaks in a relay circuit?

An inverted polarized diode. Signup and view all the answers

Which statement is true about LED connections?

LED requires proper anode and cathode connection to emit light. Signup and view all the answers

What is a likely outcome if a LED is connected backwards?

It could become permanently non-functional. Signup and view all the answers

Which of the following describes a 'quick burning' method for destroying a LED?

By connecting it incorrectly to a power supply briefly. Signup and view all the answers

What is the primary function of an oscillator circuit in a microcontroller?

To provide an accurate and stable periodic clock signal Signup and view all the answers

Which of the following is NOT a clocking option available in the PICmicro family?

Digital pulse generator Signup and view all the answers

What determines how quickly a microcontroller executes its instructions?

The frequency of the clock signal Signup and view all the answers

What property of quartz crystals is utilized in crystal oscillators?

Piezo-electric properties Signup and view all the answers

How does the resistor-capacitor (R-C) clock function in oscillators?

Through the charging time constant of the resistor-capacitor combination Signup and view all the answers

Which component is primarily responsible for the oscillation in a crystal oscillator?

Quartz crystal Signup and view all the answers

Which of the following best describes one of the advantages of crystal oscillators?

They provide a stable frequency with minimal deviation. Signup and view all the answers

What occurs when a voltage is applied to a quartz crystal in a crystal oscillator?

It causes mechanical distortion. Signup and view all the answers

What is the primary function of the 4x4 Matrix Membrane Keypad?

To provide a human interface for microcontroller projects Signup and view all the answers

Which feature of the 4x4 Matrix Membrane Keypad aids in installation?

Adhesive backing Signup and view all the answers

How does a matrix keypad determine which button has been pressed?

By combining inputs from rows and columns Signup and view all the answers

What is an economic benefit of the 4x4 Matrix Membrane Keypad?

It has a high price/performance ratio Signup and view all the answers

What does each key in a matrix keypad connect to?

One row and one column Signup and view all the answers

What is a characteristic feature of the 4x4 Matrix Membrane Keypad?

Ultra-thin design Signup and view all the answers

In the context of user interfaces, why is the 4x4 Matrix Membrane Keypad considered useful?

It offers a compact user input solution Signup and view all the answers

What type of projects commonly use the 4x4 Matrix Membrane Keypad?

Microcontroller projects Signup and view all the answers

What is the most suitable power supply voltage for the PIC16F887 microcontroller?

5V DC Signup and view all the answers

What component is used to provide stable voltage for the PIC microcontroller?

LM7805 Signup and view all the answers

How does the reset signal function for the microcontroller?

It applies a logic zero to the reset pin. Signup and view all the answers

What is the purpose of the 10K resistor connected to the MCLR pin?

To prevent shorting the 5V rail to ground. Signup and view all the answers

What is the active state for the reset signal in microcontrollers?

Low Signup and view all the answers

What happens when the reset button is pushed on the PIC microcontroller?

The program execution restarts from the beginning. Signup and view all the answers

What is the maximum current provided by the LM7805 for the microcontroller operation?

1A Signup and view all the answers

Which of the following statements is true regarding the PIC microcontroller's reset function?

The reset signal allows the microcontroller to recover from faults. Signup and view all the answers

Which port should be selected for connecting switches and push-buttons to ensure effective input signal reception?

Port B Signup and view all the answers

What role does a relay serve in a circuit controlled by a microcontroller?

To switch on/off high-power devices Signup and view all the answers

What is a key characteristic of port pins in the microcontroller?

They can be configured as input or output Signup and view all the answers

Why is it advisable to enable interrupts on PORTB pins?

To react quickly to input signal changes Signup and view all the answers

When designing a device, which factor determines the choice of ports for connection?

The type of input/output signals required Signup and view all the answers

What is the main advantage of using a relay in a microcontroller circuit?

It allows control of high-current devices with lower current Signup and view all the answers

Which port supports analog input pins in addition to digital configurations when using the microcontroller?

Port A Signup and view all the answers

What happens to the relay when the microcontroller sends a control signal?

The relay opens or closes depending on the signal Signup and view all the answers

Study Notes

PIC Microcontroller Overview

Essential components for operation: Power Supply, Reset Signal, Clock Signal.

Power Supply

PIC16F887 operates optimally at 5V DC, commonly regulated using the LM7805 for voltage stability.
LM7805 provides up to 1A current to ensure normal operation of the microcontroller and peripherals.

Reset Signal

Logic high (VCC) must be applied to the reset pin to initialize operation; reset is active LOW.
Reset functionality allows the microcontroller to revert to normal conditions; initiated by applying 0V to the MCLR pin using a push button.
A 10K resistor is utilized to connect the MCLR pin to 0V without shorting the power supply.

PIC Oscillator

Oscillator circuits generate accurate and stable clock signals for microcontrollers, with frequencies ranging from kilohertz to megahertz.
Speed of instruction execution in a microcontroller is determined by the clock signal frequency.
Four clocking options available: external oscillator, R-C clock, ceramic resonator, crystal oscillator.

Types of Oscillator Circuits

Common types include Resistor-Capacitor oscillators and Crystal oscillators.
Crystal oscillators leverage the piezoelectric properties of quartz to maintain stable frequencies during operation.

PIC 16F877A Ports

Selection of ports is crucial for communication between the microcontroller and peripherals.
Digital I/O can use any port; analog inputs require specific port configurations.
Port B is ideal for connecting switches and push-buttons due to integrated pull-up resistors, allowing for quick input response via interrupts.

Additional Components: Relays

Relays act as electrical switches governed by an external circuit and are used to control high-power devices (motors, heaters, etc.).
Safeguarding against voltage spikes is achieved through an inverted polarized diode placed parallel to the relay coil, preventing high-voltage self-induction.

Additional Components: LED Diodes

LEDs require proper polarity; connecting backwards results in permanent failure.
LEDs must not exceed their maximum current; excessive current can lead to slow or immediate destruction.

Additional Components: LCD Display

Details specific to LCD displays were not provided but are essential for human interface applications.

Additional Components: Keypad

The 4x4 Matrix Membrane Keypad consists of 16 buttons, functioning as a human interface for microcontrollers.
Features include ultra-thin design and adhesive backing for easy mounting in various applications.
Operates using a matrix formation of four rows and four columns to communicate button states to the microcontroller.

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Description

This quiz covers the fundamental requirements for operating a PIC microcontroller, including the necessary power supply, reset signal, and clock signal. Ideal for students enrolled in the ELE 575 course, this quiz will help reinforce your understanding of microcontroller basics.

PIC Microcontroller Basics - ELE 575