***ENGINEER IN THE SOCIETY*** PART 2

Roles of Professional Engineering Bodies in Nigeria


COREN
The Council for the Regulation of Engineering in Nigeria

The Council for the Regulation of Engineering in Nigeria, COREN, was established by decree 55 of 1970 and amended by Decree 27 of 1992, now the “Engineers (Registration, etc) Act, CAP E11 of 2004” Law of the Federal Republic of Nigeria.The Act establishes COREN as a statutory body of the Federal Government empowered to regulate the Practice of Engineering in all aspects and ramifications in Nigeria.
The current President of COREN is Engr. Kashim A. Ali, FNSE, mni

The Federal Government of Nigeria empowered the Council to regulate and control the training and practice of engineering in Nigeria and to ensure and enforce the registration of all engineering personnel (i.e. Engineers, Engineering Technologists, Engineering Technicians, and Engineering Craftsmen) and consulting firms wishing to practice or engage in the practice of engineering.
*Anybody, corporate or individual employer who engages the services of unregistered engineering personnel or consulting firms commits an offence against the law of the land as stipulated in clause 13(6), page 14 of the coren decrees.


This discussion will focus on Registered Engineer's status

The COREN decree specifies that: A Registered Engineer shall use the abbreviation "Engr" before his name
e.g Engr Oluseyi Basorun

Entry Qualifications into Engineer's Cadre

Person desiring to become a registered Engineer must meet the following

1. Univeristy Route -B. Sc, B. Eng, B. Tech in Engineering must have four (4) years post-graduate experience which must be under the supervision of a senior registered Engineer.

2. Polytechnic Route - HND in an Engineering field + COREN accredited PGD in the same field e.g. HND Electrical Engineering + PGD Electrical Engineering. Must have acquired a minimum of (6) years post-graduate experience which must be under the supervision of a senior registered Engineer.

3. Membership of Engineering professional bodies e.g Corporate Membership of NSE, although recently COREN returned back to conducting interviews and test for prospective candidates.

Benefit of COREN

1. Coren keeps the register of all registered engineering personnel in Nigeria. This data can be verified on http://portal.coren.gov.ng/Account/MemberSearch
2. COREN regulates the practise of engineering in Nigeria
3. Issuance of practising license to engineering personnel and engineering firms
4. Control of quakery in the practise
etc. etc.

visit COREN website for more information www.coren.gov.ng
sources: www.coren.gov.ng  www.nse.org.ng

Engr. Oluseyi Basorun mnse

*** Next, The Nigerian Society of Engineers

***ENGINEER IN THE SOCIETY***
NIEEE Lagos Chapter Whatsapp Presentation, August 2016

* ENGINEERING PRACTICE IN NIGERIA

The practice of engineering is within the domain of societal interests, that is, engineering practice has an inherent impact on society. Much of the impact is based upon that relationship the engineer has with the society.
Engineering practise is guided by professional codes of conducts put together by professional bodies e.g COREN, NIEEE and NSE in Nigeria. An engineer's conduct (as captured in professional codes of conduct)is toward other engineers, toward employers, toward clients, and toward the public. Codes of professional conduct lay out a road map for professional relationships.

* WHO IS AN ENGINEER?

From hindustantimes.com   "Engineers are people who solve problems and focus on making things work more efficiently and effectively. They apply the theories and principles of science and mathematics to research and develop economical solutions to technical problems"
Also from dictionary.com   "Engineer is a person trained and skilled in the design, construction, and use of engines or machines, or in any of various branches of engineering : e.g a mechanical engineer, a civil engineer, an electrical engineer
Bringing it closer to us.." An electrical engineer is someone who designs and develops new electrical equipment, tests equipment and solves electrical problems. They work with all kinds of electronic devices, from the smallest pocket devices to large supercomputers. Electrical engineering deals with electricity, electro-magnetism and electronics".

By manipulating basic theories in mathematics and science, engineers apply their technical knowledge to conceive, design and implement new processes, products and systems that make our everyday lives easy...
Through innovation, creativity and change Engineers provide cutting edge technology for our safety, health, security, comfort and entertainment.
As an engineer you might be on the team that develop the next generation communication gadget, or a medical device that will help doctors treat an illness, or a spacecraft that will carry humans to Mars, a satellite monitoring system to stop Boko haram insurgence and traffic robbery, or a system that can bring clean water to an underdeveloped region in Nigeria, or a new power source that is sustainable and provides clean energy for remote villages, or a device that can detect toxic agents and chemicals, an energy efficient building or an earthquake safe world, or even an electrical system for a multi-million rice processing plant. the list is endless.

Some traits of Engineers are:-
•Desire to Figure Things out. ...
•Applied Creativity. ...
•Maths Skills. ...
•Electro-mechanical Skills. ...
•Listening and Problem-Solving Skills. ...
•Interpersonal and Leadership Skills

* QUALITIES OF A PROFESSIONAL ENGINEER

Some of the characteristics and qualities of great professional engineers are enumerated below:-

1.Possesses Strong Analytical Sense: A professional engineer has excellent analytical skillsets and is continually examining systems and thinking of ways to help things work better. They are naturally inquisitive, want to know whys..and whats..

2.Pays Attention to Detail: A professional engineer must pay meticulous attention to detail. The slightest error can cause an entire electrical system to fail or cause injury to people, so every detail of make of the systems must be reviewed thoroughly in the course of the project.

3.Has Excellent Communication Skills: A professional engineer is a good communicator. one of the greatest tasks of an engineer is to translate complex  technical jagons into plain English or other agreed formats of communication.He's also saddled with the responsibility of communicating verbally with clients, other engineers, technicians and stakeholders working together on a project.

4.He takes part in Continuing Professional Education: Every practicing engineer must stay on top of latest developments in the industry. Changes in technology happen rapidly, and the most successful engineers keep abreast of new research and ideas. Continuous professional development programmes must be encouraged by NIEEE, NSE and COREN and similar professional bodies. This may even form part of requirements for re-certification of membership.

5. Creativity: A great professional engineer is very creative and always thinks of new and innovative ways to develop new systems and make existing solutions work more efficiently. Finding alternative resolution and new ideas are germane quality of engineers.

6. Possess Ability to Think Logically: A professional engineer has top-notch logical skillset, largely due to background in problem modelling. They are able to make sense of complex systems and understand how things work and how problems arise. This opens up our problem solving methodology approach and our ability to figure out where the problem stems from and quickly develop a solution.

7.Is Mathematically Inclined: A great professional engineer has excellent math skills. Engineering involves complex calculations of varying difficulties, these problems can be modeled mathematically and knowledge of Algebra, Calculus, complex functions can be readily applied to solve for needed parameters.

8.Is a Team Player: A great engineer understands that he is a part of a larger team working together towards successfully delivery of projects, therefore he must be able to integrate and play well as part of that team.

9. Has Excellent Technical Knowledge: Professional engineer has a vast amount of technical knowledge. They understand a variety of computer programs and other systems that are commonly used during an engineering project. Knowledge of working tools like Autocad, Solidworks, Matlab etc. is highly essential.

>>>>Watchout for ***ENGINEER IN THE SOCIETY*** PART 2

Roles of Professional Engineering Bodies in Nigeria

Engr. Oluseyi Basorun mnse

Mobile Device Insecurity : Need for us to be at alert!!

The growth of mobile devices in Nigeria has increased astronomically. According to statistics from www.martins.com.ng, Nigeria has 93 million mobile subscribers, representing 16% of Africa total of 620 million mobile phone connections as of September 2011. This is huge, and it places a lot of challenges on the shoulders of IT and Telecommunication practitioners in the country.  In the area of IT security, we have recorded a sharp increase in vulnerabilities risk level since we have these devices around. Mobile devices are transforming quickly into a solid and viable candidate to replace our current and typical computing platforms—including the PC and laptop. Many of these new tablets have microprocessor speed of up to 1.6GHZ Quad core, 2 GB RAM, with highly enhanced graphics.Following Moore’s Law, chip makers are now on the path to deliver 32nm system-on-a-chip (SoC) technology, which will enable more powerful computing capacity in a new breed of smaller devices. These devices will offer users an enriched experience when accessing the Internet and a whole new set of multimedia applications like 3D games and video. The features are promising in terms of the applications and solutions that people think their lives are a lot easier with these more powerful and energy-saving technology.

  A lot of owners of these sophisticated gadgets work in enterprise organization and also have their corporate office information like email, client data, mounted on their devices. Because the Internet is becoming increasingly open to hackers, crackers,phishers and ransom wares, there is need for us to be careful in the way we use these devices, especially in the work places. In most cases, we have these devices permanently connected to unsecured wireless networks which are potential sources of vulnerabilities, most of such WiFi connections open our personal information to the dangers of being hacked and exposed. With the advent of CBN cashless society in some part of the country, many transactions are going to be done electronically. There is need for a more robust identity management for mobile devices when using them to make electronic transactions and other e-commerce activities. A recent research conducted by one of the BIG 4 professional services firms, affirms that 70% of WIFI in Lagos metropolitan are running on very weak security platform. With many of them implementing clearly weak 128-bit wep key security code. Certainly, this calls for caution on the part of users and the operators/security experts need to develop solutions at Application layer for these mobile devices to secure sensitive information such as emails, personal information, debit card data, or access financial services.

To minimize these risks, it is necessary to protect the user’s identity to avoid fraud against their financial assets. 3G and Network measures are already deployed for smartphones, relying on several methods to protect data in transit. Unfortunately, these standards only work at the data-link and network layers, not at the application layer, which is most commonly used by individuals to conduct e-commerce transactions.

Some possible remediation:-

1. Tokenization, this technology has being implemented by some banks within the country for inter-bank fund transactions. It's based on multi-factor authentication method. For safe mobile banking transactions, users are encouraged to sign-up for multiple-authentication factor (Password and Hard token) to access their mobile banking platform. Even when mobile devices are stolen or accessed by unauthorized user, one is assured that access to banking profile will be minimal and safe.

2. Another viable option is to encrypt external data storage cards (SD cards), where most of personal and corporate information are kept. This will surely go a long way in securing data, as access to it will be highly restricted- the data can only be viewed on the mobile device used for the encryption.

3. Mobile Antivirus/Intrusion detection, there are several mobile antivirus apps that can be downloaded to prevent data leakages on our mobile devices.These free mobile security applications prevents the devices from being infected by virus and malware and also provide the much needed alerts when anomalies are noticed on our devices. Examples are Avast and McAfee mobile security apps to mention few.

On a closing note, mobile device owners have responsibility of protecting the 'data-ware' residing on their phones and in line with the current practice in advanced countries, IT and Telecommunication security practitioners in Nigeria to step up their games in ensuring we have an intrusion-free mobile service platforms.

Thank you

Engr. Oluseyi Basorun mnse,cissp

James Prescott Joule and the Joule Apparatus

James Prescott Joule, a scientist who successfully demonstrated the interrelationship between different forms of energy.   In this article we’ll focus on one of his experiments, the Joule Apparatus.

Back in the 1840s Joule built his Apparatus, a device which demonstrated the interrelationship between different forms of energy.

The Joule Apparatus consisted of a weight suspended by string over a pulley, which in turn was wound around a winding drum.   As long as the drum remained stationary, the weight remained motionlessly suspended.   While motionless, the weight’s potential energy lay latent within it.

 But when the pressure keeping the winding drum stationary was released, the weight was set free to fall, and its potential energy began converting to kinetic.   In the process, the string begin to unwound from the drum, which caused the drum to turn and along with it the paddle wheel it was attached to.

Joule’s Apparatus followed energy through many forms.  From the quiet of potential energy to the kinetic energy demonstrated by the falling weight.   The kinetic energy in turn was converted into mechanical energy, made manifest by the interaction between the moving drum and paddle wheel.   The rotating paddles agitated the water, causing its temperature to rise.    Observing this, Joule concluded that the mechanical energy of the spinning paddle wheel had been converted into heat energy, which temperature measurement proved was transferred into the water.   Joule’s experiment thus proved the link between potential, kinetic, mechanical, and heat energies.

Joule’s work paved the way to make possible the later development of a host of modern mechanical devices that also converted heat energy into mechanical energy, or vice versa.   These devices include a car’s engine and your kitchen’s refrigerator.

Culled from http://www.engineeringexpert.net

My xmas message to my family

My Xmas message to my family

Pulse Width Modulation

Pulse Width Modulation (PWM) can be defined as the technique of  modulating or varying the width of the pulse of a square wave signal. Pulse width modulation (PWM) is a powerful technique for controlling analog circuits with  digital outputs.

PWM founds a lot of applications in the following fields:-
- In communication systems, it is also known as pulse duration modulation (PDM). It's a digital modulation technique where the width of the modulation carrier is vary in accordance with the modulation voltage.  This results to encoding information for transmission.
- In electrical motor control system, it is an effective method of controlling the speed of a DC motor, this is achieved through delivering energy in a succession of pulses rather than a continuously varying (analog) signal. By increasing or decreasing pulse width, the controller regulates energy flow to the motor shaft.
- In inverter system, it helps in  giving a steady output voltage of 240V  AC irrespective of the load.

Within the analogue world, PWM can be implemented by applying modulated input voltage applied at the control voltage input of a 555 timer configured as a monostable multivibrator. The output pulse at the output pin 3 is modulated by the control voltage of the input pin 5. The output pulse width tw is governed by equation tw=1.1RaC as shown below.

 Also a simple comparator with a sawtooth carrier can also turn a sinusoidal command into a pulse-width modulated output, in general, the larger the command signal, the wider the
pulse.

PWM can be implemented in software using microcontroller.  By using a high-resolution counters, the duty cycle of a square wave is modulated to encode a specific analog signal level. The PWM signal is still digital because, at any given instant of time, the full DC supply is either fully on or fully off.

Microcontrollers are digital devices that understands binary signals, and the best representation of a binary signal is a square wave. The diagram below is a square wave showing the basic terminologies associated with a square wave signal. 

.

From the diagram above, it is  important to note that in a PWM signal  the TIME-PERIOD and hence the frequency is always fixed. Only the ON TIME and OFF TIME of the pulse i.e (duty cycle) varies. The term duty cycle describes the proportion of ON TIME to the regular interval or TIME PERIOD. With this, we modulate the given voltage. The difference between a square wave signal and PWM signal is that the square wave signal has same ON and OFF time (50% duty cycle), whereas a PWM signal has a variable duty cycle.
The square wave can be taken as a special case of the PWM signal which has 50% duty cycle (ON time = OFF time).
All microcontrollers features a set number of PWM pins. These are pins that have CCP (compare capture pwm).  PWM can be implemented using PIC MCU family. PIC 18F4458 is considered for the purpose of this write-up.

PWM Calculations

There are three crucial registers  must be taken into account for Pulse width modulation: PR2, and CCPRXL:CCPXCON[5:4]. Configuring the PR2 register, will allow you to configure the PWM period while selecting a proper the value for CCPRXL:CCPXCON[5:4] will allow you to choose the right duty cycle. For choosing the right value for the PR2 register, use the following equation…

 Tosc is the the inverse of the frequency that your microcontroller is running at. Also, use a prescale of 16 . For CCPRXL:CCPXCON[5:4], we will use the following equation…

CCPRXL:CCPXCON[5:4] is a 10 bit number. To make things easy make sure you convert your number to a 10 bit binary number. After you convert the number to a binary number, set your CCPRXL register to the first 8 MSB numbers. Finally, take the last 2 LSB and you use it for your CCPXCON[5:4]. Summary of the setup procedure for PWM operation  are found below:

1. Set the PWM period by writing to the PR2

register.

2. Set the PWM duty cycle by writing to the

CCPR1L register and CCP1CON<5:4> bits.

3. Make the CCP1 pin an output by clearing the

appropriate TRIS bit.

4. Set the TMR2 prescale value, then enable

Timer2 by writing to T2CON.

5. Configure the CCP1 module for PWM operation

Getting down with PIC16F87X Microcontroller

Introduction
Embedded microcontrollers are everywhere in today's world, as you might know microcontroller and microprocessor  have substantially change our electronics lives . In an average household you will find them in cell phones, TV, calculators, remote control, air conditioner, microwave oven and MP3 players etc. Hardly  will any new appliance gets home without at least one controller. For example, in an  MP3 player, one controller could be for button and display, another for converting the music from digital format to something we can hear, etc. Nowadays, electronics device and circuit are mostly design as software running within microcontrollers, and these little devices can do so much beyond our imaginations. So electronics today are blend of hardware and software.
Microcontroller are simple to use, you don't need to be an expert in electronics before you start using them, all you need to get started is the basic understanding of electronics and digital circuits. Once you get your grips on it, that's it.
This write-up is  focused on  the overview of the PIC microcontroller internal architecture, describing the features of the 16F87X specifically.

What is a microcontroller?
Microcontrollers and microprocessors are integrated circuits, but they differ fundamentally from other ICs. The designers of microcontrollers have not made them to do a particular job. As such when
you buy them, you can not specify what function it will do, until you get home and configure it as you desire. Thus a microprocessor or microcontroller can be configured to check the status of a button, and then turn a motor ON or OFF. While the same IC can be configured later, to read the status of an infra-red sensor, decode the signal and turn another device ON or OFF. If these two types of circuits were to be made using conventional digital ICs, it would have required a large number of components. Moreover any change in the specification, like change of Infra-Red codes would result in total change in design.
The ability to configure microcontroller is called programming. A program is nothing but a series of instructions, in a correct and logical manner to instruct the microprocessor respond to various inputs. Microcontrollers are programmed to do a specific job, and these jobs could vary from changing TV channels to controlling industrial processes.

PIC Microcontroller
A company named Microchip® made its first simple microcontroller, which they called PIC. Originally this was developed as a supporting device for PDP computers to control its peripheral devices, and therefore named as PIC, Peripheral Interface Controller. Thus all the chips developed by Microchip® have been named as a class by themselves and called PIC.

The PIC16F87X is a family member of PIC CMOS FLASH-based 8-bit microcontrollers. It's upward compatible with the PIC16C5x, PIC12Cxxx and PIC16C7x devices. It features 200 ns instruction execution, 256 bytes of EEPROM data memory, self programming, an ICD, 2 Comparators, 8 channels of 10-bit Analog-to-Digital (A/D) converter, 2 capture/compare/PWM functions, a synchronous serial port that can be configured as either 3-wire SPI or 2-wire I2C bus, a USART, and a Parallel Slave Port.

Organisation of  PIC Microcontroller
The Figure above shows the pin out details of a very popular 40-pin PIC microcontroller, PIC16F87X, as you can see that each pin has been assigned a number of functions. Sometimes two and sometimes three. This situation is very common in microcontrollers, as there is always more which your microcontroller can offer, yet the number of pins on a given package is limited. In a given application a pin is usually tied to a specific job, and all functionality of a pin is usually not required, however you can use the specific pin your own way. The specific function of a pin is selected by configuring various bits of internal registers. The number and names of these special function registers (SFRs) vary from device to device as some devices have limited functionality while others have more. The selection and settings of these SFR’s is the key to successful programming. It is of best interest to go through the data sheets of the device before starting programming.

Features

High-Performance RISC CPU

Ø   Lead-free; RoHS-compliant

Ø   Operating speed: 20 MHz, 200 ns instruction cycle

Ø   Operating voltage: 4.0-5.5V

Ø   Industrial temperature range (-40° to +85°C)

Ø   15 Interrupt Sources

Ø   35 single-word instructions

Ø   All single-cycle instructions except for program branches (two-cycle)

Special Microcontroller Features

Ø   Flash Memory: 14.3 Kbytes (8192 words)

Ø   Data SRAM: 368 bytes

Ø   Data EEPROM: 256 bytes

Ø   Self-reprogrammable under software control

Ø   In-Circuit Serial Programming via two pins (5V)

Ø   Watchdog Timer with on-chip RC oscillator

Ø   Programmable code protection

Ø   Power-saving Sleep mode

Ø   Selectable oscillator options

Ø   In-Circuit Debug via two pins

Peripheral Features

Ø   33 I/O pins; 5 I/O ports

Ø   Timer0: 8-bit timer/counter with 8-bit prescaler

Ø   Timer1: 16-bit timer/counter with prescaler

Ø   Can be incremented during Sleep via external crystal/clock

Ø   Timer2: 8-bit timer/counter with 8-bit period register, prescaler and postscaler

Ø   Two Capture, Compare, PWM modules

Ø   16-bit Capture input; max resolution 12.5 ns

Ø   16-bit Compare; max resolution 200 ns

Ø   10-bit PWM

Ø   Synchronous Serial Port with two modes:

Ø   SPI Master

Ø   I2C Master and Slave

Ø   USART/SCI with 9-bit address detection

Ø   Parallel Slave Port (PSP)

Ø   8 bits wide with external RD, WR and CS controls

Ø   Brown-out detection circuitry for Brown-Out Reset

Ø   Analog Features

Ø   10-bit, 8-channel A/D Converter

Ø   Brown-Out Reset

PROGRAM MEMORY (FLASH): This is used for storing a written program. Since memory made in FLASH technology can be programmed and cleared more than once, it makes this microcontroller suitable for device development. 

EEPROM - This is a non-volatile data memory that are used in computer and other computerized system and which needs to be saved when there is no power supply. It is usually used for storing important data that must not be lost if power supply suddenly stops. For instance, one such data is an assigned temperature in temperature regulators. If during a loss of power supply this data was lost, we would have to make the adjustment once again upon return of supply. Thus our device looses on self-reliance. 

RAM- Data memory used by program during its execution. RAM stores all inter results or     temporary data during run-time. Ports are physical connections between the microcontroller and the outside world. PIC16F87X has five I/O ports and 33 pins in all 5 ports.

FREE-RUNTIMER  is an 8-bit register inside a microcontroller that works independently of the program. On every fourth clock of the oscillator it increments its value until it reaches the maximum (255), and then it starts counting over again from zero. As we know the exact timing between each two increments of the timer contents, timer can be used for measuring time which is very useful with some devices.

CENTRAL PROCESSING UNIT has a role of connective element between other blocks in the microcontroller. It coordinates the work of other blocks and executes the user program.

CISC, RISC

This term is related to computerised devices, and it needs to be explained here in more detail. Harvard architecture is a newer concept than von-Neumann's. It rose out of the need to speed up the work of a microcontroller. In Harvard architecture, data bus and address bus are separate. Thus a greater flow of data is possible through the central processing unit, and of course, a greater speed of work. Separating a program from data memory makes it further possible for instructions not to have to be 8-bit words. PIC16F87X uses 14 bits for instructions which allows for all instructions to be one word instructions. It is also typical for Harvard architecture to have fewer instructions than von-Neumann's, and to have instructions usually executed in one cycle. Microcontrollers with Harvard architecture are also called "RISC microcontrollers". RISC stands for Reduced Instruction Set Computer. Microcontrollers with von-Neumann's architecture are called 'CISC microcontrollers'. Title CISC stands for Complex Instruction Set Computer. Since PIC16F87X is a RISC microcontroller, that means that it has a reduced set of instructions, more precisely 35 instructions. (Ex. Intel's and Motorola's microcontrollers have over hundred instructions) All of these instructions are executed in one cycle except for jump and branch instructions. According to what its maker says, PIC16F87X usually reaches results of 2:1 in code compression and 4:1 in speed in relation to other 8-bit microcontrollers in its class.

REGISTERS
Special Function Registers
The Special Function Registers are registers used by the CPU and peripheral modules for controlling the desired operation of the device. These registers are implemented as static RAM. The Special Function Registers can be classified into two sets: core (CPU) and peripheral.

Status Registers
These registers contains the arithmetic status of the ALU, the RESET status and the bank select bits for data memory.The STATUS register can be the destination for any instruction, as with any other register. 

 USART
The Universal Synchronous Asynchronous Receiver Transmitter (USART) module is one of the two serial I/O modules. (USART is also known as a Serial Communications Interface or SCI.) The USART can be configured as a full duplex asynchronous system that can communicate with peripheral devices such as CRT terminals and personal computers, or it can be configured as a half duplex synchronous system that can communicate with peripheral devices such as A/D or 40 D/A integrated circuits, serial EEPROMs etc. The USART can be configured in the following modes:
• Asynchronous (full duplex)
• Synchronous - Master (half duplex)
• Synchronous - Slave (half duplex)

ANALOG-TO-DIGITAL CONVERTER (A/D) MODULE
The Analog-to-Digital (A/D) Converter module has five inputs for the 28-pin devices and eight for the other devices. The A/D conversion of the analog input signal results in a corresponding 10-bit digital number. The A/D converter has a unique feature of being able to operate while the device is in SLEEP mode. To operate in SLEEP, the A/D clock must be derived from the A/D‟s internal RC oscillator. The A/D module has four registers. These registers are:
• A/D Result High Register (ADRESH)
• A/D Result Low Register (ADRESL)
• A/D Control Register0 (ADCON0)
• A/D Control Register1 (ADCON1)

INTERRUPTS

The PIC16F87X family has up to 14 sources of interrupt. The interrupt control register (INTCON) records individual interrupt requests in flag bits. It also has individual and global interrupt enable bits. A global interrupt enable bit, GIE (INTCON<7>) enables (if set) all unmasked interrupts, or disables (if cleared) all interrupts. When bit GIE is enabled, and an interrupt‟s flag bit and mask bit are set, the interrupt will vector immediately. Individual interrupts can be disabled through their corresponding enable bits in various registers. Individual interrupt bits are set, regardless of the status of the GIE bit.

INSTRUCTION 

Each PIC16F87X instruction is a 14-bit word, divided into an OPCODE which specifies the instruction type and one or more operands which further specify the operation of the instruction. The PIC16F87X instruction set summary in byte-oriented, bit-oriented, and literal and control operations.
All instructions are executed within one single instruction cycle, unless a conditional test is true or the program counter is changed as a result of an instruction. In this case, the execution takes two instruction cycles with the second cycle executed as a NOP. One instruction cycle consists of four oscillator periods. Thus, for an oscillator frequency of 4 MHz, the normal instruction execution time is 1 μs. If a conditional test is true, or the program counter is changed as a result of an instruction, the instruction execution time is 2μs.

APPLICATIONS
PIC16F87X find it's place in most simple and complex microcontroller projects, some of these can be LCD, Access control and surveillance, Home automation, Digital display, Robotic and industrial instrumentation control projects.